INDIVIDUAL WATER
SUPPLY SYSTEMS
U. S. DEPARTMENT OF
HEALTH, EDUCATION, AND WELFARE
Public Health Service
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INDIVIDUAL WATER
SUPPLY SYSTEMS
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U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Division of Environmental Engineering & Food Protection
Special Engineering Services Branch
Washington 25, D. C.
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Public Health Service Publication No. 24
(Revised 1962)
UNITED STATES GOVERNMENT PRINTING OFFICE
WASHINGTON t 1962
Far tale by the Superintendent of Document*, U.S. Government Printing Office
Washington 25, D.C. - Price 40 ctnli
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Foreword
In the preparation of this manual, the Public Health Service was
fortunate to have the advisory assistance of the Joint Committee on
Rural Sanitation. This committee is composed of specialists from
Governmental and other agencies interested in and acquainted with
problems concerning the development and operation of individual
water supply systems. Their comments, thoughts, and suggestions,
based on many years of experience, were invaluable in the preparation
of this manual. The following individuals constitute the current
Committee membership:
U.S. DEPARTMENT or AGRICULTURE :
Agricultural Research Service;
John W. Hockey, Ass't. Chief, Livestock Engineering and
Farm Structures Research Branch, Agricultural Engineering
Research Division.
Farmers' Home Administration:
William V. Albright, Agricultural Engineer.
Federal Extension Service:
H. S. Pringle, Extension Agricultural Engineer.
Forest Service:
R. M. Peterson, Water and Structures Branch,
Division of Engineering.
AMERICAN PUBLIC HEALTH ASSOCIATION :
Professor John E. Kiker, Jr., Head, Sanitary Engineering
Section, Civil Engineering Department, University of Florida.
U.S. COAST GUARD :
Captain James H. LeVan, Chief Sanitary Engineer Officer.
CONFERENCE OP MUNICIPAL PUBLIC HEALTH ENGINEERS :
William H. Gary, Jr., Chief, Bureau of Environmental Health,
D.C. Department of Public Health.
CONFERENCE OF STATE SANITARY ENGINEERS :
Robert M. Brown, Chief, Bureau of Environmental Hygiene,
Maryland State Department of Health.
FEDERAL HOUSING ADMINISTRATION :
James R. Simpson, Chief, Standards and Studies Section.
U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE :
Office of Education:
John L. Cameron, Chief, School Housing Section.
Public Health Service:
Malcolm C. Hope, Sanitary Engineer Director.
(Committee Chairman)
Arthur H. Neill, Sanitary Engineer Director.
(Committee Secretary)
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U.S. DEPARTMENT OP INTERIOR :
U.S. Geological Survey :
Clyde S. Conover, District Engineer, Ground-Water Branch,
Water Resources Division.
TENNESSEE VALLEY AUTHORITY :
F. E. Gartrell, Assistant Director of Health.
VETERANS ADMINISTRATION :
Herbert W. Schmitt, Supervisory Land Planner,
Loan Guaranty Service.
WATER POLLUTION CONTROL FEDERATION :
David B. Lee, Director, Bureau of Sanitary Engineering,
Florida State Board of Health.
INDUSTRY ADVISORS WERE AS FOLLOWS :
G. F. Briggs, National Water Well Association.
R. G. Breeden, Water Systems Council.
P.H.S. ADVISORS WERE AS FOLLOWS :
C. C. Johnson, Jr., Division of Indian Health.
Richard L. Woodward, Division of Water Supply and Pollution
Control.
Gordon G. Robeck, Division of Water Supply and Pollution
Control.
The Public Health Service has also drawn freely from the experi-
ence and suggestions received from various State, university, and in-
dustry publications on the subject. Several illustrations were taken
or adapted from these sources. Preparation of the original draft re-
vision was undertaken by Dr. Gerald T. Orlob. Under the general
supervision of Malcolm C. Hope, Assistant Chief, Division of En-
vironmental Engineering and Food Protection, and the immediate
direction of Arthur H. Neill, Chief, Special Engineering Services
Branch, Mr. Sandier H. Dickson, Senior Assistant Sanitary Engineer,
PHS, assumed the major responsibility for its production.
WESLEY E. GILBERTSON, Chief
Division of Environmental Engineering
and Food Protection
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Preface
An essential requirement for healthful and comfortable living is a
dependable supply of water for drinking and other domestic uses. This
supply should be palatable, convenient, of good quality, and adequate
in quantity.
In suburban areas the consumer is well advised to obtain water from
an existing or extended public water supply system, thus acquiring the
advantages of qualified supervision and a measure of assurance re-
garding the quality and quantity of the water needed for his health
and comfort. Because of the public health control usually given to
those public water supplies which are owned or directly controlled by
a governmental organization, their use is recommended wherever
practicable.
This manual is a revision of PHS Publication No. 24, Individual
Water Supply Systems, issued in 1950. The updating reflects chang-
ing trends in the problems of individual water supply systems and in-
cludes additional and new information in this field which has come
to the attention of the Public Health Service. While establishing
uniform practice among various Federal agencies concerned with the
sanitation of individual water supplies, it is hoped that the manual
will be useful to State and local health authorities, well-drillers, in-
dustry groups, and others concerned with the development and opera-
tion of such supplies. This manual emphasizes the sanitation aspects
of small supply systems such as those serving individual dwellings,
farms, rural schools or similar institutions, recreational or tourist ac-
commodations, camps, or other installations not having access to
public water supply systems. The recommended practices should be
helpful in the design, construction, and operation of these types of
private and quasi-public systems.
Assistance in the planning of such water supply systems is usually
available from State or local health departments, county agricultural
agents, water supply consultants, and geologists. Similarly qualified
individuals are also in a position to advise on various aspects of water
supply development projects. Before the design and construction of
an individual water supply system have been made, the particular
standards or regulations of the State, local health, or other authorities
having jurisdiction should be consulted. Similarly, an individual
should seek legal advice if any question of water rights is involved.
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The individual considering the development of a water supply sys-
tem should carefully consider the factors which will determine its
feasibility. Before one begins any design or construction, he should
acquaint himself with several things.
1. The potential sources of water supply
2. The quality requirements which must be met in order to pro-
vide a safe and economical supply
3. The quantity of water which is required for the uses
contemplated
4. The effects of the development of the same water sources by
others
5. The legal right to the use of the water sources
After the necessary factors have been considered, the design, con-
struction, and operation of the individual water supply system should
provide the most practical solution to the water supply problem, con-
sistent with local conditions and intended objectives. It is the intent
of this manual to provide information on essential requisites for an
adequate and acceptable water supply system and methods for their
attainment. This manual is not intended to take the place of expert
advice needed for the solution of specific water supply problems.
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Contents
Page
Foreword.. — iii
Preface v
PART I. SELECTION OP A WATER SOURCE
Rights to Use of Water 1
Sources of Water Supply. _ 1
Ground Water 2
Surface Water 4
Ground and Surface Water 5
Snow, Hail, Sleet.__ 5
Quality of Water 5
Physical Characteristics 6
Chemical Characteristics 7
Biological Factors 11
Radiological Factors 13
Quantity of Water 13
Average Daily Water Use 14
Peak Demands 14
Special Water Considerations 14
Sanitary Survey 18
Ground-Water Supplies.- 19
Surface-Water Supplies— 19
PART II. GROUND WATER
Rock Formations and Their Water-Bearing Proper-
ties 21
Ground-Water Basins 22
Sanitary Quality of Ground Water 22
Distances to Sources of Contamination 23
Development of Ground Water 24
Development by Wells 26
Yield of Wells 28
Preparation of Ground Surface at Well Site 29
Types of Wells _ 31
Construction of Wells 31
Setting Screens or Slotted Casings in Wells 39
Development of Wells 40
Testing Well for Yield and Drawdown _. 40
Sanitary Protection of Wells __ 41
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Page
Well Covers and Seals 42
Disinfection of Wells 43
Abandonment of Wells 47
Reconstruction of Existing Dug Wells 48
Special Considerations in Constructing Artesian
Wells 48
Development of Springs 48
Sanitary Protection of Springs.._ 50
Disinfection of Springs 51
Infiltration Galleries 51
PART III. SURFACE WATER FOR RURAL USE
Sources of Surface Water 53
Controlled Catchments... 54
Ponds or Lakes 58
Streams 63
Irrigation Canals 63
PART IV. WATER TREATMENT
Need and Purpose 64
Sedimentation 65
Coagulation 65
Filtration 65
Disinfection -- 67
Chemical Disinfection 67
Chlorination Equipment 71
Superchlorination-Dechlorination 72
Chlorination Control 73
Heat Treatment 74
Other Methods and Materials for Water Disin-
fection 74
Conditioning 75
Iron and/or Manganese 75
Iron Bacteria 76
Softening 76
Fluoridation 78
Tastes and Odors -- 78
Hydrogen Sulfide 79
Corrosion Control 79
Corrosion and Scale Relationship 80
Prevention of Corrosion 80
Algae Control 81
Aeration 82
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PART V. PUMPING, DISTRIBUTION, AND STORAGE
Page
Pumping -- 84
Types of Well Pumps... 84
Selection of Pumping Equipment 86
Sanitary Protection of Pumping Facilities 90
Pumphousing and Appurtenances __ 93
Pitless Units 93
Distribution 95
Pipe and Fittings 95
Pipe Capacity and Head Loss 97
Protection of Distribution Systems 100
Disinfection of Water Distribution Systems 100
Storage 101
Determination of Storage Volume 101
Protection of Storage Facilities _ 102
BIBLIOGRAPHY 106
APPENDICES
A. Recommended Procedure for Cement Grouting of
Wells for Sanitary Protection 108
B, Bacteriological Quality 110
C. Emergency Disinfection 111
D. Suggested Ordinance 113
INDEX
LIST OF TABLES
Table
1. Planning guide for water use 16
2. Rates of flow for certain plumbing, household,
and farm fixtures 18
3. Minimum recommended distances between
water supplies and various sources of con-
tamination — 24
4. Characteristics of various types of wells 30
5. Recommended mechanical analysis of slow
sand filter media 66
6. Approximate maximum tolerance limits of
various fish to copper sulfate 81
7. Information on pumps 88
8. Allowance in equivalent length of pipe for
friction loss in valves and threaded fittings— 99
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LIST OF ILLUSTRATIONS
Figure Page
1. Hydrologic cycle 3
2. Pumping effects on aquifers 27
3. Dugwell 32
4. Bored well with driven well point 34
5. Driving methods 37
6. Drilled well 38
7. Sanitary well seals — 42
8. Spring protection 49
9. Yield of impervious catchment areas 55
10. Cistern 57
11. Pond 59
12. Pond water-treatment system 61
13. Jet pumps 87
14. Components of total operating head in well
pump installations 92
15. Pumphouse 94
16. Pitless units 96
17. Head loss vs. pipe size 98
18. Typical concrete reservoir 103
19. Typical valve and box, manhole covers, and
piping installations 104
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Part I
Selection of a
Water Source
The planning of an. individual water supply system requires a. deter-
mination of the quality and quantity of the water and available
sources. In addition, it is desirable for one to have a basic knowledge
of water rights and the hydrological, geological, chemical, biological,
and possible radiological factors affecting the water. These factors
are usually interrelated because of the continuous circulation of the
water or water vapor from the oceans to the air, over the surface of
the land and underground, and back to the oceans. This circulation
is called hydrologic cycle. (See fig. 1, p. 3.)
RIGHTS TO THE USE OF WATER
The right of an individual to use of water for domestic, irrigation,
or other purposes varies in different States. Some water rights stem
from ownership of the land bordering or overlying the source, while
others are acquired by a performance of certain acts required by law.
There are three basic types of water rights. They are:
Riparian—rights which are acquired together with title to the
land bordering or overlying the source of water.
Appropriative—rights which are acquired by following a specific
legal procedure.
Prescriptive—lights which are acquired by diverting and putting
to use, for a period specified by statute, water to which other
parties may or may not have prior claims. The procedure
necessary to obtain prescriptive rights must conform with the
conditions established by the water rights laws of individual
States.
When there is any question regarding the right to the use of water,
the property owner should consult the appropriate authority in his
State and clearly establish his rights to its use.
SOURCES OF WATER SUPPLY
At some time in its history, water resided in the oceans. By evapo-
ration, moisture is transferred from the ocean surface to the atmos-
phere, where the winds cany the moisture-laden air over land masses.
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Under certain conditions, this water vapor condenses to form clouds,
which release their moisture as precipitation in the form of rain, hail,
sleet, or snow.
When rain falls toward the earth, a part may evaporate and return
immediately to the atmosphere. Precipitation in excess of the amount
that wets a surface or supplies evaporation requirements is available
as a potential source of water supply.
Ground Wafer
A part of the precipitation may infiltrate into the soil. This water
replenishes the soil moisture or is used by growing plants and, re-
turned to the atmosphere by transpiration. Water that drains down-
ward below the root zone finally reaches a level at which all of the
opening's or voids in the earth's materials are filled with water. This
zone is known as the zone of saturation. Water in the zone of satura-
tion is referred to as ground water. The upper surface of the zone
of saturation, if not confined by impermeable material, is called the
"water table." When an overlying impermeable formation confines
the water in the zone of saturation under a pressure greater than
atmospheric pressure, the ground water is under artesian pressure.
The name "artesian" comes from the ancient province of Artesium in
France where in the days of the Romans water flowed to the surface
of the ground from a well. Not all water from wells that penetrate
artesian formations flows above the surface of the land. For a well
to be artesian, the water in the well must stand above the top of the
aquifer. An aquifer or water-bearing formation is an underground
layer of permeable rock or soil which permits the passage of water.
The porous material just above the water table may contain water
by capillarity in the smaller void spaces. This zone is referred to as
the capillary fringe. It is not a source of supply since the water held
will not drain freely by gravity.
Because of the irregularities in underground deposits and in surface
topography, the water table occasionally intersects the surface of the.
ground or the bed of a stream, lake, or ocean. As a result, ground
water moves to these locations and out of the aquifer or ground-water
reservoir. Thus, ground water is continually moving within the
aquifer even though the movement may be slow. The water table or
artesian pressure surface slopes from areas of recharge to areas of
discharge. The pressure differences represented by these slopes cause
the flow of ground water within the aquifer. At any point the slope
is a reflection of the rate of flow and resistance to movement of water
through the saturated formation. Seasonal variations in the supply
of water to the underground reservoir cause considerable changes in
the elevation and slope of the water table and artesian pressure level.
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PRECIPITATION
I
WATER TABLE IUNCONFINEDI AQUIFER
Water-Table Cr0(j
Well
NONFLOWING
ARTESIAN WJU
ROCK' ' ^ry^—_____^£x
FIGURE 1. HYDROLOGIC CYCLE.
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Wells
A well that penetrates the water table can be used to extract water
from the ground-water reservoir. The removal of well water by
pumping will cause a lowering of the water table near the well. If
pumping of a well or a number of wells continues at a rate that
exceeds the one at which the water may be replaced by the water-
bearing formations, the sustained yield of the aquifer is exceeded.
If wells extract water from an aquifer over a period of time at a rate
such that the aquifer will become depleted or bring about other unde-
sired results, then the "safe yield" of the aquifer is exceeded. Under
these conditions, salt-water encroachment may occur in wells located
near the seashore or other surface or underground saline waters.
Springs
Ground water that flows upon the land surface or into a body of
surface water is called a spring. Depending upon whether they
discharge from a water table or an artesian aquifer, springs may flow
by gravity or by artesian pressure. The flow from a spring may
vary considerably. When the water table or artesian pressure fluctu-
ates, so does the flow of springs. For further discussion see part II.
Surface Wafer
Surface water is made up of direct runoff and base flow. Precipita-
tion that does not enter the ground through infiltration or is not
returned to the atmosphere by evaporation flows over the ground
surface and is classified as direct runoff. Direct runoff is water that
moves over saturated or impermeable surfaces, and in stream channels
or other natural or artificial storage sites. The dry weather (base)
flow of streams is derived from ground water.
In some areas, a source of water for individual development is the
rainfall intercepted by roof surfaces on homes, barns, or other build-
ings. Water from such impermeable surfaces can be collected and
stared in tanks called cisterns. In some instances, natural ground
surfaces can be conditioned to make them impermeable. This con-
ditioning will increase runoff to cisterns or large artificial storage
reservoirs, thereby reducing loss by infiltration into the ground.
Runoff from ground surfaces may be collected in either natural or
artificial reservoirs. A portion of the water stored in surface
reservoirs is lost by evaporation and from infiltration to the ground
water table from the pond bottom. Transpiration from vegetation in
and adjacent to ponds constitutes another means of water loss.
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Ground and Surface Wafer
Ground water may become surface water at springs or at inter-
sections of a water body and a water table. During extended dry
periods, stream flows consist largely of water from the ground-water
reservoir. As the ground-water reservoir is drained by the suface
stream, the flow will reach a minimum or may cease altogether. It
is important in evaluating stream and spring supplies to consider
seasonal fluctuations in flow, the advantages of surface storage, and
the benefits derived from minimum depletion of ground-water
reserves.
Snow, Hail, and Sleet
Much of the snow, hail, or sleet falling on a water shed is kept in
storage on the ground surface until temperatures rise above freezing.
In the mountainous areas of the Western United States, snow storage
is an important source of water supply through much of the normal
irrigation season. Measures taken to increase the snowpack and
reduce the melt rate are usually beneficial to individual water supply
systems in these areas.
QUALITY OF WATER
Precipitation in the form of rain, snow, hail, or sleet contains very
few impurities. It may contain trace amounts of mineral matter,
gases, and other substances as it forms and falls through the earth's
atmosphere. The precipitation, however, has virtually no bacterial
content.
Once precipitation reaches the earth's surface, many opportunities
are presented for the introduction of mineral and organic substances,
microorganisms, and other forms of pollution (contamination).1
When water runs over or through the ground surface it may pick up
particles of soil. This is noticeable in the water as cloudiness or
turbidity. It also picks up particles of organic matter and bacteria.
As surface water seeps downward into the soil and through the under-
lying material to the water table, most of the suspended particles are
filtered out. This natural filtration may be partially effective in
removing bacteria and other particulate materials; however, the
chemical characteristics of the water may change and vary widely
when it comes in contact with mineral deposits.
1 Pollution as used in this manual means the presence in water of any foreign
substances (organic, inorganic, radiological, or biological) which tend to lower
its quality to a point that it constitutes a health hazard or impairs the usefulness
of the water. Contamination (Included in the broad definition of pollution) is
the presence of an Infectious agent on a body surface or on an inanimate article
or substance.
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The widespread use of synthetically produced chemical compounds,
including pesticides and insecticides, has caused a renewed interest in
the pollution of water. Many of these materials are known to be
toxic and others have certain undesirable characteristics which inter-
fere with the use of the water even when present in relatively small
concentrations. In recent years instances of water pollution have been
traced to a sewage or waste water source containing synthetic deter-
gents. Typically, concentrations of synthetic detergents containing
alkyl benzene sulfonate (ABS) in amounts less than 0.5 mg/1 are
rarely detected without chemical analysis. The user should understand
that if ABS is reaching the water supply, other materials which may
be hazardous or impart undesirable characteristics may also gain
entrance.
Agents which alter the quality of water as it moves over or below
the surface of the earth may be classified under four major headings.
1. Physical.—Physical characteristics relate to the quality of
water for domestic use and are usually associated with the ap-
pearance of water, its color or turbidity, temperature, taste, and
odor in particular.
2. Chemical.—Chemical differences between waters are sometimes
evidenced by their observed reactions, such as the comparative
performance of hard and soft waters in laundering.
3. Biological.—Biological agents are very important in their rela-
tion to public health and may also be significant in modifying
the physical and chemical characteristics of water.
4. Radiological,—Radiological factors must be considered in areas
where there is a possibility that the water may have come in
contact with radioactive substances.
Consequently, in the development of an individual water supply
system, it is necessary to examine carefully all the factors which might
adversely affect the intended use of a water supply source.
Physical Characteristics
The water as used should be free from all impurities which are
offensive to the sense of sight, taste, or smell. The physical charac-
teristics of the water include turbidity, color, taste and odor, and
temperature.
Turbidity: The presence of suspended material such as clay, silt,
finely divided organic material, plankton, and other inorganic material
in water is known as turbidity. Turbidities in excess of 5 units are
easily detectable in a glass of water, and are usually objectionable for
aesthetic reasons.
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Clay or other inert suspended particles in drinking water may not
adversely affect health, but water containing such particles may re-
quire treatment to make it suitable for its intended use. Following
a rainfall, variations in the ground water turbidity may be considered
an indication of surface or other introduced pollution.
Color: Dissolved organic material from decaying vegetation and
certain inorganic matter cause color in water. Occasionally, excessive
blooms of algae or the growth of aquatic microorganisms may also im-
part color. While color itself is not usually objectionable from the
standpoint of health, its presence is aesthetically objectionable and
suggests that the water needs appropriate treatment.
Taste and Odor: Taste and odor in water can be caused by foreign
matter such as organic compounds, inorganic salts, or dissolved gases.
These materials may come from domestic, agricultural, or natural
sources. Acceptable waters should be. free from any objectionable
taste or odor at point of usage. Knowledge concerning the chemical
quality of a water supply source is important in order to determine
what treatment, if any, is required to make the water acceptable for
domestic use.
Temperature: The most desirable drinking waters are consistently
cool and do not have temperature fluctuations of more than a few
degrees. Ground water and surface water from mountainous areas
generally meet these criteria. Most individuals find that water having
a temperature between 50°-60° F. is most palatable.
Chemical Characteristics
The nature of the rocks that form the earth's crust affects not only
the quantity of water that may be recovered but also its characteristics.
As surface water seeps downward to the water table, it dissolves
portions of the minerals contained by soils and rocks. Ground water,
therefore, can often contain more dissolved minerals than surface
water.
The chemical characteristics of water in a particular locality can
sometimes be predicted from analyses of adjacent water sources.
These data are often available in published reports of the U.S. Geo-
logical Survey or from Federal, State, and local health, geological,
and water agencies. In the event that the information is not avail-
able, a chemical analysis of the water source should be made. Some
State health and geological departments, as well as State colleges,
and many commercial laboratories have the facilities and may be able
to provide this service.
The chemical analysis of a domestic water supply will ordinarily
include the determination of total hardness, alkalinity, pH, and the
presence of sulfates and chlorides. In some areas chemical analyses
647085 O—62 2 7
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for the presence of certain nitrogen compounds and radicals, iron,
manganese, flourides, and other substances may be necessary. The
size of sample required and the method of collection should be in ac-
cordance with recommendations of the facility making the analysis.
The following is a discussion of the chemical characteristics of water
based on the limits established by the 1962 Public Health Service
Drinking Water Standards.2
Toxic Substances: Water may contain toxic substances in solution.
If analysis of the water supply shows that these substances exceed
the following concentrations, the supply should NOT be used.
Substances
Arsenic (As)
Bjvrium (B&)
Cftdmium (Cd)
Chromium (Cr+8)
Milligrams
per liter !
0.05
1. 00
0. 01
0, 05
Substances
Cyanides (CN)
Lead (Pb)
Selenium (Se)
Silver (Ag)
Milligrams
per liter l .
0.2,
0.05
0.01
0,05
1 The term "parts per million (ppm)" is currently being replaced by the term
"milligrams per liter (mg/l)," "Milligrams per liter" is defined as the quantity
of matter in milligrams present in a liter of solution. For water, the ppm and
mg/1 are approximately equal.
Chlorides: Most waters contain some chloride in solution. The
amount present can be caused by the leaching of marine sedimentary
deposits, by pollution from sea water, brine, or industrial and domestic
wastes. Chloride concentrations in excess of about 250 mg/1 usually
produce a noticeable taste in drinking water. Domestic water should
contain less than 100 mg/1 of chloride. In areas where the chloride
content is higher than 100 mg/1 and all other criteria are met, it may
be necessary to use a water source which exceeds this limit.
An increase in chloride content in water may indicate possible
pollution from sewage sources, particularly if the normal chloride
content is known to be low.
Copper: Copper is found in some natural waters, particularly in
areas where these ore deposits have been mined. Copper in small
amounts is not considered detrimental to health, but will impart an
undesirable taste to the drinking water. For this reason, the
recommended limit for copper is 1.0 mg/1.
Fluorides: In some areas water sources contain natural fluorides.
Where the concentrations approach optimum levels, beneficial health
1 U.S. Department of Health, Education, and Welfare, "1962 Public Health
Service Drinking Water Standards." Public Health Service Publication No. 936
(1962).
8
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effects have been observed. In such areas the incidence of dental
caries has been found to be below the rate in areas without natural
fluorides.3 The optimum fluoride level for a given area depends upon
air temperature since that is what primarily influences the amount of
water people drink. Optimum concentrations from 0.7 to 1.2 mg/1
are recommended. Excessive fluorides in drinking water supplies may
produce fluorosis (mottling) of teeth, which increases as the optimum
fluoride level is exceeded. The State or local health departments,
therefore, should be consulted for their recommendations.
Iron: Small amounts of iron are frequently present in water be-
cause of the large amount of iron present in the soil. The presence
of iron in water is considered objectionable because it imparts a
brownish color to laundered goods and affects the taste of beverages
such as tea and coffee. Recent studies indicate that eggs spoil faster
when washed in water containing iron in excess of 10 mg/1. The
recommended limit for iron is 0.3 mg/1.
Lead: A brief or prolonged exposure of the body to lead can be
seriously injurious to health. Prolonged exposure to relatively small
quantities may result in serious illness or death. Lead taken into the
body in quantities in excess of certain relatively low "normal" limits
is a cumulative poison. A maximum concentration of 0.05 mg/1 of
lead in water must not be exceeded. When a concentration of 0.05
mg/1 of lead is exceeded, a more suitable source of water supply should
be found.
Manganese: There are two reasons for limiting the concentration
of manganese in drinking water: (1) to prevent aesthetic and eco-
nomic damage, and (2) to avoid any possible physiological effects
from excessive intake. The domestic user finds that manganese pro-
duces a brownish color in laundered goods, and impairs the taste of
beverages, including coffee and tea. The recommended limit for
manganese is 0.05 mg/1.
Nitrates: Nitrate (NO3) has caused methomoglobinemia (infant
cyanosis or "blue baby disease") in infants who have been given
water or fed formulas prepared with water having high nitrates. A
domestic water supply should not contain nitrate concentrations in
excess of 45 mg/1. Nitrates in excess of normal concentrations, often
in shallow wells, may be an indication of seepage from livestock
manure deposits. When the presence of high nitrate concentrations
is suspected, the advice of local health authorities should be secured.
* It Is a known fact that the addition of about 1 mg/1 of fluoride to water
supplies will help to prevent tootb decay in children. Some natural water
supplies already contain amounts of fluoride which exceed the recommended
optimum concentrations-
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Sodium: When it is necessary to know the precise amount of sodium
present in a water supply, a laboratory analysis should be made.
When home water softeners utilizing the ion exchange method are
used the amount of sodium will be increased. For this reason, water
that has been softened should be analyzed for sodium when a precise
record of individual sodium intake is recommended.
The presence of sodium in water may affect persons suffering from
heart, kidney, or circulatory ailments. Persons so affected should rely
on their physicians' advice. When a strict sodium-free diet is recom-
mended, any water should be regarded with suspicion. In light of
the preceding facts and because individual intake of sodium varies,
no recommended limit for sodium has been established.
Sulfates: Waters containing high concentrations of sulf ate caused
by the leaching of natural deposits of magnesium sulf ate (Epsom
salts) or sodium sulf ate (Glauber's salt) may be undesirable because
of their laxative effects. Sulfate content should not exceed 250 mg/1.
Zinc: Zinc is found in some natural waters, particularly in areas
where these ore deposits have been mined. Zinc is not considered
detrimental to health, but it will impart an undesirable taste to drink-
ing water. For this reason, the recommended limit for zinc is 5.0
mg/1.
Chemical terms
Alkalinity: Alkalinity is imparted to water by bicarbonate, car-
bonate, or hydroxide components. The presence of these compounds
is determined by standard methods involving titration with various
indicator solutions. Knowledge of the alkalinity components is useful
in the treatment of water supplies.
Hardness: Hard water and soft water are relative terms. Hard
water retards the cleaning action of soaps and detergents, causing an
expense in the form of extra work and cleaning agents. Furthermore,
when hard water is heated it will deposit a hard scale (as in a kettle,
heating coils, or cooking utensils) with a consequent waste of fuel.
Calcium and magnesium salts, which cause hardness in water
supplies, are divided into two general classifications: carbonate or
temporary hardness and noncarbonate or permanent hardness.
Carbonate or temporary hardness is so called because heating the
water will largely remove it. When the water is heated, bicarbonates
break down into insoluble carbonates that precipitate as solid par-
ticles which adhere to a heated surface and the inside of pipes.
Noncarbonate or permanent hardness is so called because it is not
removed when water is heated. Noncarbonate hardness is due largely
to the presence of the sulfates and chlorides of calcium and mag-
nesium in the water.
10
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pH: pH is a measure of the hydrogen ion concentration in water.
It is also a measure of the acid or alkaline content. pH values range
from 0 to 14—1 indicating neutral water; values less than 7, increas-
ing acidity; and values greater than 7, increasing alkalinity. The pH
of water in its natural state often varies from 5.5 to 9.0. Determina-
tion of the pH value assists in the control of corrosion, the determina-
tion of proper chemical dosages, and adequate control of disinfection.
Biological Factors
Water for drinking and cooking purposes must he made free from
disease-producing organisms. These organisms include bacteria, pro-
tozoa, virus, and helminths (worms).
Contamination of Water Supplies
Some organisms which cause disease in man originate with the fecal
discharges of infected individuals. It is seldom practical to monitor
and control the activities of human disease-carriers. For this reason,
it is necessary to exercise precautions against contamination of a
normally safe water source or to institute treatment methods which
will produce a safe water.
Unfortunately, the specific disease-producing organisms present in
water are not easily identified. The techniques for comprehensive
bacteriological examination are complex and time-consuming. It has
been necessary to develop tests which indicate the relative degree of
contamination in terms of an easily defined quantity. The most
widely used test involves estimation of the number of bacteria of the
coliform group, which are always present in fecal wastes and out-
number disease-producing organisms. The coliform group normally
inhabit the intestinal tract of man, but are also found in most domestic
animals and birds, as well as certain wild species.
Bacteriological Quality
The Public Health Service Drinking Water Standards have estab-
lished limits for the mean concentration of coliform bacteria in a
series of water samples and the frequency at which concentrations may
exceed the mean. The results are expressed in terms of the "most-
probable number" (MPN) by the reporting laboratory. This term
is actually an estimate based on certain probability formulas. The
recommended standards for drinking water are roughly equivalent to
restricting the coliform concentration to not more than one organism
for each one hundred milliliters of water.4
* One hundred milliliters is about one-half cup in volume.
11
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Application of the Public Health Service Drinking Water Stand-
ards to individual water supplies is difficult due to the low frequency
with which samples can be properly collected and examined. Bac-
teriological examinations indicate the presence or absence of contam-
ination in the collected sample only, and are indicative of quality only
at the time of collection. A sample positive for coliforms is a good
indication that the source may have been contaminated by surface
washings or fecal material. On the other hand, a negative result can-
not be considered assurance of a continuously safe supply unless the
results of a thorough sanitary survey of a surrounding area, together
with subsequent negative samples, support this position.
Collection of Samples for Bacteriological Examination
For a reliable indication of the bacteriological safety of an individ-
ual water supply, the owner should depend on the experience of quali-
fied public health personnel. Special precautions are necessary in
the collection of water samples, and proper training and experience
are essential in evaluating the analytical results. Before a sample is
collected, the examining facility should be contacted to obtain its
recommendations. In the event that a procedure is not given, one
should follow the suggestions found in appendix B, p. 110.
Other Biological Factors
Certain forms of aquatic vegetation and microscopic animal life in
natural water may be either stimulated or retarded in their growth
cycles by physical, chemical, or biological factors. For example, the
growth of algae, minute green plants usually found floating in surface
water, is stimulated by light, heat, and the presence of carbon dioxide
from the respiration of animals or as a product of organic decom-
position. Their growth may, in turn, be retarded by changes in pH
(measure of acidity), the presence of inorganic impurities, excessive
cloudiness or darkness, and the presence of certain bacterial species.
Continuous cycles of growth and decay of algal cell material may
result in the production of noxious by-products which may adversely
affect the quality of a water supply. The same general statements
may be made regarding the growth cycles of certain nonpathogenic
bacteria or microcrustacea which inhabit natural waters.
A water source should be as free from biological activity as possible.
Biological activity can be avoided or kept to a minimum by:
1. Selecting water sources which do not normally support much
plant or animal life.
2. Protecting the supply against subsequent contamination by
biological agents.
12
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3. Minimizing entrance of fertilizing materials such as organic
and commercial minerals.
4. Controlling the light and temperature of stored water.
5. Providing treatment for the destruction of biologic life or its
by-products.
Ratfiofogicaf Factors
The development and use of atomic energy as a power source and
mining of radioactive materials have made it necessary to establish
limiting concentrations for the intake into the body of radioactive
substances, including drinking water.
The effects of human exposure to radiation or radioactive materials
are viewed as harmful and any unnecessary exposure should be
avoided. The concentrations of radioactive materials specified in the
current U.S. Public Health Service Drinking Water Standards are
intended to limit the human intake of these substances so that the
total radiation exposure of any individual will not exceed those defined
in the Radiation Protection Guides recommended by the Federal
Radiation Council. Man has always been exposed to natural radia-
tion from water, food, and air. The amount of radiation to which
the individual is normally exposed varies with the amount of back-
ground radioactivity. Water with high radioactivity is not normal
and is confined in great degree to areas of man-made nuclear activity.
Radiological data indicating both background and other forms of
radioactivity in an area may be available in publications of the TJ.S.
Public Health Service; U.S. Geological Survey; or from Federal,
State, or local agencies. For information or recommendations on
specific problems, the appropriate agency should be contacted.
QUANTITY OF WATER
One of the first steps in the selection of a suitable water supply
source is determining the demand which will be placed on it. The
essential elements of water demand include the average daily water
consumption and the peak rate of demand. The average daily water
consumption must be estimated:
1. To determine the ability of the water source to meet continuing
demands over critical periods when surface flows are low and
ground-water tables are at minimum elevations and
2. For purposes of estimating quantities of stored water which
would sustain demands during these critical periods.
The peak demand rates must be estimated in order to determine
plumbing and pipe sizing, pressure losses, and storage requirements
13
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necessary to supply sufficient water during periods of peak water
demand.
Average Daily Water Use
Many factors influence water use for a given system. For example,
the mere fact that water under pressure is available stimulates its use,
often excessive, for watering lawns and gardens, for washing automo-
biles, for operating air-conditioning equipment, and for performing
many other utility activities at home and on the farm. Modern
kitchen and laundry appliances, such as food waste disposers and
automatic dishwashers, contribute to a higher total water use and tend
to increase peak demands. Since water requirements will influence
all features of an individual development or improvement, they must
figure prominently in plan preparation. Table 1, p. 16, presents a
summary of average water use as a guide in preparing estimates, with
local adaptations where necessary.
Peak Demands
The rate of water use for an individual water system will vary
directly with domestic activity in the home or with the operational
farm program. Rates are generally highest in the home near meal-
times, during midmorning laundry periods, and shortly before bed-
time. During the intervening daytime hours and at night, water use
may be virtually nil. Thus, the total amount of water used by a
household may be distributed over only a few hours of the day, during
which the actual use is much greater than the average rate determined
from table 1, p. 16.
Simultaneous operation of several plumbing fixtures will determine
the maximum peak rate of water delivery for the home water system.
For example, a shower, an automatic dishwasher, a lawn-sprinkler
system, and a flush valve toilet all operated at the same time would
probably produce a near critical peak. It is true that not all of these
facilities are usually operated together; but if they exist on the same
system, there is always a possibility that a critical combination may
result, and for design purposes this method of calculation is sound.
Table 2, p. 18, summarizes the rate of flow which would be expected
for certain household and farm fixtures.
Spec/of Water Considerations
Lawn Sprinkling-. The amount of water required for lawn sprin-
kling depends upon the size of the lawn, type of sprinkling equipment,
climate, soil, and water control. In dry or arid areas the amount
of water required may equal or exceed the total used for domestic or
farmstead needs. When lawn watering in relation to other water
uses is small, the water requirements can be estimated. For estimat-
14
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ing purposes, a rate of approximately % inch per hour of surface
area is reasonable. This amount of water can be applied by sprin-
kling 30 gallons of water per hour over each 100 square feet.
Example:
-7^—- X 30=300 gallons per hour or 5 gpm.
100
A lawn of 1000 square feet would require 300 gallons per hour.
When possible the water system should have a minimum capacity
of 500-600 gallons per hour. A water system of this size may be able
to operate satisfactorily during a peak demand. Peak flows can be
estimated by adding lawn sprinkling to peak domestic flows but not
to fire flows.
Fire Protection: In areas of individual water supply systems,
effective firefighting depends upon the facilities provided by the prop-
erty owner. The National Fire Protection Association has prepared
a report which outlines and describes ways to utilize available water
supplies.8
The most important factors in successful firefighting are early dis-
covery and immediate action. For immediate protection portable
fire extinguishers are desirable. Such first aid protection is designed
only for the control of fires in the early stage; therefore, a water
supply is desirable as a second line of defense.
The use of gravity water supplies for firefighting presents certain
basic problems. These include (1) the construction of a dam, farm
pond, or storage tank to hold the water until needed and (2) the deter-
mination of the size of pipeline installed from the supply. The size
of the pipe is dependent upon two factors: (1) the total fall or head
from the point of supply to the point of use and (2) the length of
pipeline required.
Wells can serve as a source of water for both domestic and fire-
fighting purposes. A well should be capable of supplying 8-10 gal-
lons per minute for a period of 2 hours daily throughout the year.
Drilled, deep wells are the most dependable for firefighting, drawing
their supply from extensive aquifers. The slightly greater cost of
a 6-inch drilled well is easily justified by the increased supply made
available. Wells should be tested for yield by pumping for a period
of at least 2 hours. The results of the test will indicate the equip-
ment to be purchased.
The smallest commercial water pressure systems have a capacity of
210 gallons an hour (3^ gallons per minute) or even less. While
this will furnish a stream, through ordinary garden hose, of some
"National Fire Protection Association, "Water Systems for Fire Protection
on Farms," National Fire Codes, Vol. IV (Boston, 1946).
15
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value in combating incipient fires or in wetting down adjacent build-
ings, it cannot be expected to be effective on a fire which has gained
any headway. When such systems are already installed, connec-
tions and hose should be provided. When a new system is being
planned or a replacement of equipment made, it is urged that a capac-
ity of at least 500 gallons an hour (8^ gallons per minute) be speci-
fied and the supply increased to meet this demand. If necessary,
storage should be added. The additional cost for the larger unit
necessary for fire protection is partially offset by the increased quan-
tities of water available for other uses.
Table 1.—Planning guide for water use
Types of establishments
Gallons
per day
Airports (per passenger) 3-5
Apartments, multiple family (per resident) _ 60
Bath houses (per bather) 10
Camps:
Construction, semipermanent (per worker) 50
Day with no meals served (per camper) 15
Luxury (per camper) __ 100-150
Resorts, day and night, with limited plumbing (per camper) 50
Tourist with central bath and toilet facilities (per person) 35
Cottages with seasonal occupancy {per resident) 50
Courts, tourist with individual bath units (per person) 50
Clubs:
Country (per resident member) 100
Country (per nonresident member present) 25
Dwellings:
Boarding houses (per boarder) 50
Additional kitchen requirements for nonresident boarders 10
Luxury (per person) 100-150
Multiple family apartments (per resident) _. 40
Rooming houses (per resident) 60
Single family (per resident)... 50-75
Estates (per resident) _ 100-150
Factories (gallons per person per shift) 15-35
Hotels with private baths (two persons per room) 60
Hotels without private baths (per person).__ _ 50
Institutions other than hospitals (per person) _ 75-125
Hospitals (per bed) 250-400
Laundries, self-serviced (gallons per washing, i.e., per customer) 50
Livestock (per animal):
Cattle (drinking) 12
Dairy (drinking and servicing).. _ 35
Goat (drinking). 2
Hog (drinking) _ 4
Horse (drinking) ... 12
Mule (drinking) 12
Sheep (drinking).. 2
Steer (drinking) 12
16
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Types of establishments
Gallons
per day
Motels with bath, toilet, and kitchen facilities (per bed space) 50
With bed and toilet (per bed space) 40
Parks:
Overnight with flush toilets (per camper) 25
Trailers with, individual bath units (per camper) 50
Picnic:
With bath houses, showers, and flush toilets (per picnicker) 20
With toilet facilities only (gal. per picnicker) ._ __. 10
Poultry:
Chickens (per 100)_._ - 5-10
Turkeys (per 100) - 10-18
Restaurants with toilet facilities (per patron) 7-10
Without toilet facilities (per patron) _ -_ 2#-3
With bars and cocktail lounge (additional quantity per patron) 2
Schools:
Boarding (per pupil) 75-100
Day with cafeteria, gymnasiums, and showers (per pupil) 25
Day with cafeteria but no gymnasiums or showers (per pupil) 20
Day without cafeteria, gymnasiums, or showers (per pupil) 15
Service Stations (per vehicle) — 10
Stores (per toilet room) 400
Swimming pools (per swimmer) 10
Theaters:
Drive-in (per car space) 5
Movie (per auditorium seat) 5
Workers:
Construction (per person per shift) 50
Day (school or offices per person per shift) — 15
17
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Table 2.—ftafes of Row for certain plumbing, houiefio/d, and farm flx/urei
Location
Ordinary basin faucet
Self-closing basin faucet
Sink faucet, % inch-
Sink faucet, V£ inch _
Bathtub faucet ._
Laundry tub faucet, % inch
Shower
Ball-cock for closet
Flush valve for closet „ _- _
Flushometer valve for urinal
Garden hose (SO ft,, %-inch sill cock)
Garden hose (50 ft., %-inch outlet)
Drinking fountains
Fire hose 1% inches, }i-ineh nozzle
Flow pressure '
— pounds per
square inch
(psi)
g
g
8
8
8
8
8
8
15
15
30
15
15
30
Flow rate —
gallons per
minute (gpm)
2.0
2. 5
4. 5
4. 5
6. 0
5. 0
5. 0
3. 0
» 15-40
15. 0
5. 0
3. 33
0. 75
40. 0
1 Flow pressure is the pressure in the supply near the faucet or water outlet
while the faucet or water outlet is wide open and flowing.
1 Wide range due to variation in design and type of closet flush valves.
SANITARY SURVEY
The importance of a sanitary survey of water sources cannot be over-
emphasized. With a new supply, the sanitary survey should be made
in conjunction with the collection of initial engineering data covering
the development of a given source and its capacity to meet existing
and future needs. The sanitary survey should include the detection
of all health hazards and the assessment of their present and future
importance. Persons trained and competent in public health engi-
neering and the epidemiology of waterborne diseases should conduct
the sanitary survey. In the case of an existing supply, the sanitary
survey should be made at a frequency compatible with the control of
the health hazards and the maintenance of a good sanitary quality.
The information furnished by the sanitary survey is essential to
complete interpretation of bacteriological and frequently the chemical
data. This information should always accompany the laboratory
findings. The following outline covers the essential factors which
should be investigated or considered in a sanitary survey. Not all of
the items are pertinent to any one supply and, in some cases, items not
in the list would be important additions to the survey list.
18
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Ground-Wafer Supplies
a. Character of local geology; slope of ground surface.
b. Nature of soil and underlying porous strata whether clay, sand,
gravel, rock (especially porous limestone); coarseness of sand or
gravel; thickness of water-bearing stratum; depth to water table;
location and log of local wells in use or abandoned.
c. Slope of water table, preferably as determined from observational
wells or as indicated, presumptively but not certainly, by slope
of ground surface.
d. Extent of drainage area likely to contribute water to the supply.
e. Nature, distance, and direction of local sources of pollution.
f. Possibility of surface-drainage water entering the supply and of
wells becoming flooded; methods of protection.
g. Methods used for protecting the supply against pollution by means
of sewage treatment, waste disposal, and the like.
h. Well construction: material, diameter, depth of casing; depth to
well screens or perforations; length of well screens or perforations.
i. Protection of well at top and on sides.
j. Pumphouse construction (floors, drains, etc.); capacity of pumps;
drawdown when pumps are in operation.
k. Availability of an unsafe supply, usable in place of normal supply,
hence involving danger to the public health.
1. Disinfection: equipment, supervision, test kits, or other types of
laboratory control.
Surface-Wafer Supplies
a. Nature of surface geology; character of soils and rocks.
b. Character of vegetation; forests; culitvated and irrigated land,
including salinity, effect on irrigation water, etCv
c. Population and sewered population per square mile of catchment
area.
d. Methods of sewage disposal, whether by diversion from watershed
or by treatment.
e. Character and efficiency of sewage-treatment works on watershed.
f. Proximity of sources of fecal pollution to intake of water supply.
g. Proximity, sources, and character of industrial wastes, oil field
brines, acid mine waters, etc.
h. Adequacy of supply as to quantity.
i. For lake or reservoir supplies; wind direction and velocity data;
drift of pollution; sunshine data (algae).
j. Character and quality of raw water: coliform organisms (MPN),
algae, turbidity, color, objectionable mineral constituents.
19
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k. Nominal period of detention in reservoir or storage basin.
1. Probable minimum time required for water to flow from sources
of pollution to reservoir and through reservoir intake.
m. Shape of reservoir, with reference to possible currents of water,
induced by wind or reservoir discharge, from inlet to water-supply
intake.
n* Protective measures in connection with the use of watershed to
control fishing, boating, landing of airplanes, swimming, wading,
ice cutting, permitting animals on marginal shore areas and in or
upon the water, etc.
o. Efficiency and constancy of policing.
P. Treatment of water: kind and adequacy of equipment; duplica-
tion of parts; effectiveness of treatment; adequacy of supervision
and testing; contact period after disinfection; free chlorine re-
siduals carried.
q. Pumping facilities: pumphouse, pump capacity and standby units,
storage facilities.
20
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Part II
Ground Water
ROCK FORMATIONS AND THEIR WATER-BEARING PROPERTIES
The rocks that form the crust of the earth are divided into three
classes:
1. Igneous—rocks which are derived from the hot magma deep
in the earth. They include granite and other coarsely crystal-
line rocks, dense igneous rocks such as occur in dikes and sills,
basalt and other lava rocks, cinders, tuff, and other fragmental
volcanic materials.
2. Sedimentary—rocks which consist of chemical precipitates and
of rock fragments deposited by water, ice, or wind. They in-
clude deposits of gravel, sand, silt, clay, and the hardened
equivalents of these—conglomerate, sandstone, siltstone, shale,
limestone, and deposits of gypsum and salt.
3. Metamorphic—rocks which are derived from both igneous and
sedimentary rocks through considerable alteration by heat and
pressure at great depths. They include gneiss, schist, quartzite,
slate, and marble.
The pores, Joints, and crevices of the rocks in the zone of saturation
are generally filled with water. Although the openings in these rocks
are usually small, the total amount of water that can be stored in
the subsurface reservoirs of the rock formations is large. The most
productive aquifers are deposits of clean, coarse sand and gravel;
coarse, porous sandstones; cavernous limestones; and broken lava
rock. Some limestones, however, are very dense and unproductive.
Most of the igneous and metamorphic rocks are hard, dense, and of
low permeability. They generally yield small quantities of water.
Among the most unproductive formations are the silts and clays. The
openings in these materials are too small to yield water, and the forma-
tions are structually too incoherent to maintain large openings u*nder
pressure. Compact materials near the surface, with open joints similar
to crevices in rock, may yield small amounts of water.
21
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GROUND-WATER BASINS
In an undeveloped ground-water basin, percolation of water to lower
basins, seepage from and to surface-water sources, and transpiration
are dependent upon the water in storage and the rate of recharge.
During periods following abundant rainfall, recharge may exceed dis-
charge. When recharge exceeds discharge, the excess rainfall in-
creases the amount of water available in storage in the ground-water
basin. As the water table or artesian pressure rises, the gradients to
points of discharge become steeper and outflows increase. When re-
charge ceases, storage decrease from outflow causes water-table levels
and artesian pressures to decline. In most undeveloped basins the
major fluctuations in storage are seasonal, with the mean annual
elevation of water levels showing little variation. Thus, the average
annual inflow to storage equals the average annual outflow, a quantity
of water referred to as the basin yield.
The proper development of a ground-water source requires careful
consideration of the hydrological and geological conditions of the
area. The individual who wishes to take full advantage of a water
source for domestic use should obtain the assistance of a qualified
engineer, geologist, or contractor familiar with the construction of
wells in his area. He should rely on facts and experience, not on
instinct or intuition. Facts on the geology and hydrology of an area
may be available in publications of the U.S. Geological Survey or
from other Federal and State agencies.
SANITARY QUALITY OF GROUND WATER
When water seeps downward through the underlying material to
the water table, the particles held in suspension, including micro-
organisms, are filtered out. The number of particles removed by
filtration depends on the depth and character of the intervening soil
materials. Moreover, because the length of time and the storage con-
ditions in the aquifer are usually unfavorable to bacterial multiplica-
tion or survival, the bacterial quality of the water may improve while
it is percolating through the soil and during storage in the aquifer.
Because these organisms are smaller than most suspended particles
that cause turbidity in water, contaminated ground water may appear
clear and yet contain pathogenic organisms.
The most effective protection of ground water through natural con-
ditions is provided by an impermeable stratum of clay or hardpan
separating the overlying material from the aquifer tapped by the well.
Protection may also be provided by an overlying sand formation of
sufficient depth and character to insure good filtering action. Mini-
22
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mum filtration with little resultant protection occurs where surface
water reaches the zone of saturation through large openings such as
animal burrows, through cracks in soil or rocks, solution channels
or fissures in limestone rock, coarse gravel formations, or man-made
excavations.
In the use of shallow ground water, it should be remembered that
microorganisms reach the capillary fringe first and then the water
table. Since the water table rises during periods of heavy precipita-
tion and declines in dry periods and when wells are pumped, it is
possible for it to be in contact with a contaminated zone near the sur-
face. Wells that extend only a short distance below the water table,
therefore, are more likely to be contaminated. Good protection is
achieved through the construction of a deep well with a watertight
casing surrounded by cement grout extending a minimum of 10 feet
below the ground surface.
In areas without central sewerage systems, human excreta are
usually deposited in septic tanks, cesspools, or pit privies. Bacteria
in the liquid effluents from such installations have a good chance of
entering shallow ground-water aquifers. In some places, sewage
effluents may be discharged directly into water-bearing formations
through abandoned wells or soil-absorption systems. When this hap-
pens, the threat of ground-water contamination can be reduced by
locating a new well or by developing a spring as far from sources
of contamination as is necessary, and upgradient if possible, to insure
good water quality.
DISTANCES TO SOURCES OF CONTAMINATION
All ground-water sources should be located a safe distance from
sources of contamination. In cases where sources are severely limited,
however, a ground-water aquifer that might become contaminated
may be considered for a water supply if treatment is provided. After
a decision has been made to locate a water source in an area, it is
necessary to determine the distance the source should be placed from
the origin of contamination and the direction of water movement. A
determination of a safe distance is based on specific local factors
described in the section on "Sanitary Survey" in part I of this
manual.
Because many factors affect a determination of a safe distance
between a ground-water supply and a source of contamination, it is
impractical to set fixed distances. As a rule, the distance should be
the maximum that economics, land ownership, geology, and topogra-
phy will permit. If at all possible a well should be located on ground
that is higher than the source of contamination. Drainage that might
6470350—62 8 23
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reach the source from areas used by livestock should be diverted by
ditching.
Each installation should be inspected by a person with sufficient
training and experience to evaluate all of the factors involved.
Because some guide is needed when qualified individuals are not avail-
able, a table of minimum distances is given on page 24. Under certain
conditions these minimum recommended distances may be inadequate
and will have to be modified. Requirements of the State health
department concerned should be met.
TabU 3.—Minimum recommended d/stances between wafer tuppffet and varfovs sources of
confamfnafion l
Contamination
sources
Building sewer.
Septic tank
Disposal field
Seepage pit
Dry well
Cesspool
Well or suction
line (distance
in feet)
50
50
100
100
50
150
1 The distances given are suggested values to be used as a guide. For
specific recommendations, contact the State or local health agency.
DEVELOPMENT OF GROUND WATER
The type of ground-water development to be undertaken is depend-
ent upon the geological formations and hydrological characteristics
of the water-bearing formation. The development of ground water
falls into two main categories:
1. Development by wells
a, Nonartesian or water table
b. Artesian
2. Development from springs
a. Gravity
b. Artesian
Nonartesian wells are those that penetrate formations in which
ground water is found under water-table conditions. Pumping from
the well lowers the water table in the vicinity of the well and water
moves toward the well under the pressure differences thus artificially
created.
Artesian wells are those that penetrate aquifers in which the ground
water is found under hydrostatic pressure. Such a condition occurs
24
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in an aquifer that is confined beneath an impermeable layer of material
at an elevation lower than that of the intake area of the aquifer. The
intake areas or recharge areas of confined aquifers are commonly at
high-level surface outcrops of the formations. Ground-water flow
occurs from high-level outcrop areas to low-level outcrop areas, which
are areas of natural discharge. It also flows toward points where
water levels are lowered artificially by pumping from wells. When
the water level in the well stands above the top of the aquifer, the
well is described as artesian. A well that yields water by artesian
pressure at the ground surface is a flowing artesian well.
Gravity springs occur where water percolating laterally through
permeable material overlying an impermeable stratum comes to the
surface. They also occur where the land surface intersects the water
table. This type of spring is particularly sensitive to seasonal fluctu-
ations in ground-water storage and frequently dwindles to a seep or
disappears during dry periods. Gravity springs are characteristically
low discharge sources, but when properly developed they make satis-
factory individual water supply systems.
Artesian springs discharge from artesian aquifers. They may oc-
cur where the confining formation over the artesian aquifer is ruptured
by a fault or where the aquifer discharges to a lower topographic area.
The flow from these springs depends on the difference in recharge and
discharge elevations of the aquifer and on the size of the openings
transmitting the water. Artesian springs are usually more dependable
than gravity springs, but they are particularly sensitive to the pump-
ing of wells developed in the same aquifer. As a consequence, ar-
tesian springs may be dried by pumping.
Springs may be further classified by the nature of the passages
through which water issues from the source.
Seepage springs are those in which the water seeps out of sand,
gravel, or other material that contains many small interstices. The
term as used here includes many large springs as well as small ones.
Some of the large springs have extensive seepage areas and are usually
marked by the presence of abundant vegetation. The water of small
seepage springs may be colored or carry an oily scum because of de-
composition of organic matter or the presence of iron. Seepage
springs may emerge along the top of an impermeable bed, but they
occur more commonly where valleys are cut into the zone of saturation
of water-bearing deposits. These springs are generally free from
harmful bacteria, but they are susceptible to contamination by surface
runoff which collects in valleys or depressions.
Tubular springs issue from relatively large channels, such as the
solution channels and caverns of limestone, and soluble rocks and
smaller channels that occur in glacial drift. They are sometimes
25
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referred to as "bold" springs because the water issues freely from one
or more large openings. When the water reaches the channels by per-
colation through sand or other fine-grained material, it is usually free
from contamination. When the channels receive surface water di-
rectly or receive the indirect effluent of cesspools, privies, or septic
tanks, the water must be regarded as unsafe.
Fissure springs issue along bedding, joint, cleavage, or fault planes.
Their distinguishing feature is a break in the rocks along which the
water passes. Some of these springs discharge uncontaminated water
of deep-source origin. A large number of thermal springs are of
this type. Fissure springs, however, may discharge water which is
contaminated by surface drainage from strata close to the surface.
DEVELOPMENT BY WELLS
When a well is pumped, the level of the water table in the vicinity
of the well will be lowered. (See fig. 2, p. 27.) This lowering or
"drawdown" causes the water table or artesian pressure surface, de-
pending on the type of aquifer, to take the shape of an inverted cone
called a cone of depression. This cone, with the well at the apex,
is measured in terms of the difference between the static water level
and the pumping level. At increasing distances from the well, the
drawdown decreases until the slope of the cone merges with the static
water table. The distance from the well at which this occurs is called
the radius of influence. The radius of influence is not constant but
tends to continuously expand with continued pumping. At a given
pumping rate, the shape of the cone of depression depends on the
characteristics of the water-bearing formation. Shallow and wide
cones will form in highly permeable aquifers composed of coarse sands
or gravel. Steeper and narrower cones will form in less permeable
aquifers. As the pumping rate increases, the drawdown increases and
consequently the slope of the cone steepens. The limiting value of
the cone depends upon the characteristics of the aquifer.
The character of the aquifer—artesian or water table—and the
physical characteristics of the formation which will affect the shape
of the cone include thickness, lateral extent, and the size and grading
of sands or gravels. In a material of low permeability such as fine
sand or sandy clay, the drawdown will be greater and the radius of
influence less than for the same pumpage from very coarse gravel.
For example, when other conditions are equal for two wells, it may
be expected that pumping costs for the same pumping rate will be
higher for the well surrounded by material of lower permeability be-
cause of the greater drawdown.
26
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EFFECT OF PUMPING ON CONE OF DEPRESSION
•Discharge
Cone of Depression
Lesser Pumping Rate
Cone of Depression for
For Greater Pumping Rate
•Discharge
EFFECT OF AQUIFER MATERIAL ON CONE OF DEPRESSION
-Discharge
Static Water Table
Ground Surface
Static Water Table
Draw-Down
j
Cone of Depression
• t
a < >
i
Radius of Influence
Coarse Gravel
EFFECT OF OVERLAPPING FIELD OF INFLUENCE PUMPED WELLS
-Discharge
Discharge
'".-''
•
• * '
1
':^Frr
•
. - ^
Aquifc
-
^T*1
TS»r "!-'J'"T " ;
F*»u*E 2. PUMPING EFFECTS ON AQUIFERS.
27
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When the cones of depression overlap, the local water table will
be lowered. This requires additional pumping lifts to obtain water
from the interior portion of the group of wells. In addition, a wider
distribution of the wells over the ground-water basin will reduce the
cost of pumping and will allow the development of a larger quantity
of water.
Yield of Wells
The amount of water that can be obtained from any type of well
depends on three main factors: character of the aquifer, type and con-
struction of the well, and characteristics of the pumping equipment.
The short-term yield of a well depends mainly upon the capacity of
the pump, whereas the long-term yield depends primarily upon the
characteristics of the aquifer.
The diameter of a well pipe will affect the drawdown and the effec-
tive pumping rate. An increase in the diameter of the well pipe will
decrease the drawdown and allow an increased pumping rate. The
effect of well diameter upon discharge is important in wells with a
small diameter. There is a limiting value for the diameter of the
well beyond which it is not economically practicable to make it larger.
It is not always possible to accurately predict the yield of a given
well. Knowledge can be gained, however, from studying the geology
of the area and interpreting the results obtained from other wells
constructed in the vicinity. This information will be helpful in select-
ing the location and type of well most likely to be successful. The in-
formation can also provide an indication of the quantity or yield to
expect.
A common way to describe the yield of a well is to express its dis-
charge capacity in relation to its drawdown. This relationship is
called the specific capacity of the well and is expressed in "gallons per
minute (gpm) per foot of drawdown." The specific capacity may
range from less than 1 gpm per foot of drawdown for a poorly de-
veloped well or one in a tight aquifer to more than 100 gpm per foot
of drawdown for a properly developed well in a highly permeable
aquifer.
Table 4, p. 30, gives general information on the practicality of pene-
trating various types of geologic formations by the methods indicated.
Dug wells can be sunk only a few feet below the water table. This
seriously limits the drawdown that can be imposed during pumping,
which in turn limits the yield of the well. A dug well that taps a
highly permeable formation such as gravel may yield 10 to 30 gpm or
even more in some situations with only 2 or 3 feet of drawdown. If
the formation is primarily fine sand, the yield may be on the order of
2 to 10 gpm. These refer to dug wells of the sizes commonly used.
28
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Bored wells, like dug wells, can also be sunk only a small depth
below the static water level. A penetration of 5 to 10 feet into the
water-bearing formation can probably be achieved. If the well is
nonartesian, the available drawdown would be 2 or 3 feet less than
the depth of water standing in the well. If the well taps an artesian
aquifer, however, the static water level will rise to some point above
the top of the aquifer. This rise of the static water level increases the
depth of the water. The available drawdown and the yield of the well
will therefore be increased. A bored well tapping a highly permeable
aquifer and providing several feet of available drawdown may yield
20 gpm or more. If the aquifer has a low permeability or the depth
of water in the well is small, the yield may be much lower.
Driven wells can be sunk to as much as 30 feet or more below the
static water level. A well at this depth can provide 20 feet or more of
drawdown when being pumped. The small diameter of the well, how-
ever, limits the type of pump that can be employed, so that the yield
under favorable conditions is limited to about 30 gpm. In fin& sand
or sandy clay formations of limited thickness, the yield may be less
than 5 gpm.
Drilled and jetted wells can usually be sunk to such depths that the
depth of water standing in the well and consequently the available
drawdown will vary from less than 10 to hundreds of feet. In pro-
ductive formations of considerable thickness, yields of 300 gpm and
more are readily attained. Drilled wells can be constructed in all
instances where driven wells are used and in many areas where dug
and bored wells are constructed. The larger diameter of a drilled well
as opposed to that of a driven well permits use of larger pumping
equipment that can develop the full capacity of the aquifer. As has
already been pointed out, the capacity or yield of a well varies greatly,
depending upon the permeability and thickness of the formation and
upon the available drawdown in the well.
Prep or of ion of Ground Surface erf Well Site
A properly constructed well should exclude surface water from a
ground-water source to the same degree as does the undisturbed over-
lying geologic formation. The well site should not be subject to flood-
ing and should be graded to facilitate the rapid drainage of surface
water. The following precautions will insure reasonable protection
against entry of surface water.
1. The grade should be sloped away from the well to divert sur-
face water. The area should be filled, if necessary, graded, and
maintained to prevent the accumulation or retention of surface
29
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CO
o
Table 4.—Characteristics of various types of wells 1
Characteristics
Range of practical depths
(general order of magni-
tude)
Diameter _
Type of geologic formation:
Clay
Silt
Sand._ _ _
Gravel __
Cemented gravel
Boulders
Sandstone
Limestone __ __
Dense igneous rock
Type of Well
Dug
0-50 feet
3-20 feet
Yes
Yes
Yes
Yes
Yes
Yes
Soft
Soft, frac-
tured
No
Bored
0-100 feet
2-30 inches
Yes
Yes
Yes
Yes
No
Less than well
diameter.
Soft
Soft, frac-
tured
No
Driven
0-50 feet
l}£-2 inches
Yes
Yes
Yes
Fine
No
No
Thin layers
No
No
Drilled
Percussion
0-1000 feet
4-18 inches
Yes
Yes
Yes
Yes
Yes
(In firm
bedding)
Yes
Yes
Yes
Rotary
0-1000 feet
4—24 inches
Yes
Yes
Yes
Yes
Yes
(Difficult)
Yes
Yes
Yes
Jetted
0-100 feet
4-12 inches
Yes
Yes
Yes
%" pea gravel
No
No
No
No
No
1 The ranges of values in this table are based upon general conditions which may be exceeded for specific areas or conditions.
-------
water within 50 feet of the well in all directions. The fill may
be protected from erosion by riprap or sod where necessary.
For a well on a hillside, adequate intercepting ditches should
be constructed on the uphill side of the well to keep runoff at
least 50 feet away from it in all directions. These ditches
should have the capacity to .carry the runoff of heavy storms
and should be properly maintained.
2. Pump platforms, pumproom floors, or well covers should be
located not less than 2 feet above the highest known high-water
level of any nearby body of water. The area around the well
should be filled and graded to the necessary height.
Types of Wells
Wells may be classified with respect to construction methods as
dug, bored, driven, drilled, and jetted.
Drilled wells may be drilled by either the rotary or percussion
method.
Each type of well has distinguishing physical characteristics and
is best adapted to meet particular water-development requirements.
The following factors should be considered when choosing the type
of well to be constructed in a given situation.
1. Characteristics of the subsurface strata to be penetrated and
their influence upon the method of construction.
2. Hydrology of the specific situation and hydraulic properties
of the aquifer; seasonal fluctuations of water levels.
3. Degree of sanitary protection desired, particularly as this is
affected by well depth.
4. Cost of construction work and materials.
Construction of Wells
Dug Wells
Because they are difficult to maintain in a sanitary condition, dug
wells are not recommended if other ground-water sources can be
developed. Under certain conditions, however, they may be the most
feasible' means of obtaining water, and they can furnish a useful
supply in areas remote from sources of contamination.
Dug wells are usually excavated with pick and shovel. The ex-
cavated material can be lifted to the surface by a bucket attached to
a windlass or hoist. A power-operated clam shell or orange peel
bucket may be used in holes greater than 3 feet in diameter where
the material is principally gravel or sand. In dense clays or cemented
materials, pneumatic hand tools are effective means of excavation.
31
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Note:
Pump screen to be
placed below point
of maximum draw-down
Sanitary Wed Seal
Cobble Drain
Reinforced Concrete
Cover Slab Sloped
Away From Pump
^Surface Sol
Precast Concrete Pipe
*
Clay
Water-Bearing Gravel
FIGURE 3. DUG WELL.
32
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To prevent the native material from caving, one must place a crib
or lining in the excavation and move it downward as the pit is deep-
ened. The space between the lining and the undisturbed embankment
should be backfilled with clean material. In the region of water-
bearing formations, the backfilled material should be sand or gravel.
Cement grout should be placed to a depth of 10 feet below the ground
surface to prevent entrance of surface water along the well lining.
(See fig. 3, p. 32.)
Dug wells may be lined with brick, stone, or concrete, depending
on the availability of materials and the cost of labor. Precast con-
crete pipe, available in a wide range of sizes, provides an excellent
lining. This lining can be used as a crib as the pit is deepened.
When the lining is to be used as a crib, concrete pipe with tongue-and-
groove joints and smooth exterior surface is preferred. (See fig. 3,
p. 32.) Bell and spigot pipe may be used for a lining where it can
be placed inside the crib or in an unsupported pit. This type of pipe
requires careful backfilling to guarantee a tight well near the surface.
The prime factor with regard to preventing contaminated water from
entering a dug well is the sealing of the well lining and otherwise
excluding draining-in of surface water at and near the well.
Most dug wells do not penetrate much below the water table because
of the difficulties in manual excavation and the positioning of cribs
and linings. The depth of excavation can be increased by the use of
pumps to lower the water level during construction. Because of their
shallow penetration into the zone of saturation, many dug wells fail
in times of drought when the water level recedes or when large
quantities of water are pumped from the wells.
Bored Wells
. Bored wells are commonly constructed with earth augers turned
either by hand or by power equipment. Such wells are usually re-
garded as practical at depths of less than 100 feet when the water
requirement is low and the material overlying the water-bearing for-
mation has noncaving properties and contains few large boulders. In
suitable material, holes from 2 to 30 inches in diameter can be bored
to about 100 feet without caving.
In general, bored wells have the same characteristics as dug wells,
but they may be extended deeper into the water-bearing formation.
Bored wells may be cased with vitrified tile, concrete pipe, standard
wrought iron, steel casing, or other suitable material capable of sus-
taining imposed loads. The well may be completed by installing well
screens or perforated casing in the water-bearing sand and gravel.
Proper protection from surface drainage should be provided by seal-
ing the casing with cement grout to a depth of at least 10 feet below
the ground surface.
33
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Reinforced Concrete
Cover Slab Sloped
Away From Pump
Sanitary Well Seal
Reinforcing Steel
Artesian Pressure Surface
- Packer.;; %C^/:
Water-Bearing Sand
We'll Point
FIGURE 4. BORED WELL WITH DRIVEN WELL POINT.
34
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Driven Wells
The simplest and least expensive of all well types is the driven well.
It is constructed by driving into the ground a drive well point which
is fitted to the end of a series of pipe sections. (See fig. 4, p. 34.)
The drive point is of forged or cast steel. Drive points are usually
11/4 or 2 inches in diameter. The well is driven with the aid of a maul,
a drive shoe, or a pile driver. For deeper wells, the well points are
sometimes driven into water-bearing strata from the bottom qf a bored
or dug well. (See fig. 4, p. 34.) The yield of driven wells is gen-
erally small to moderate. Where they can be driven an appreciable
depth below the water table, they are no more likely than bored wells
to be seriously affected by water-table fluctuations. The most suitable
locations for driven wells are areas containing alluvial deposits of
high permeability. The presence of coarse gravels, cobbles, or boulders
interferes with sinking the well point and may damage the wire mesh
jacket.
When a well is driven, it is desirable to prepare a pilot hole that
extends to the maximum practical depth. This can be done with a
hand auger slightly larger than the well point. After the pilot hole
has been prepared, the assembled point and pipe are lowered into the
hole. Depending on the resistance afforded by the formation, driving
is accomplished in several ways. The pipe is driven by directly strik-
ing the drive cap, which is snugly threaded to the top of the protrud-
ing section of the pipe. A maul, a sledge, or a special driver may be
used to hand-drive the pipe. The special driver may consist of a
weight and sleeve arrangement which slides over the drive cap as the
weight is lifted and dropped in the driving process. (See fig. 5, p. 37.)
Jetted Wells
A rapid and efficient method of sinking well points is that of jetting
or washing-in. This method requires a source of water and a pressure
pump. Water forced under pressure down the riser pipe issues from
a special washing point. The well point and pipe are then pushed
down as material is loosened by the jetting.
The riser pipe of a jetted well is usually used as the suction pipe
for the pump. In such instances, surface water may be drawn into
the well if the drive pipe develops holes by corrosion. An outside
protective casing may be installed to a depth of at least 10 feet to
provide protection against the possible entry of contaminated surface
water. The annular space between the casings should then be filled
with cement grout. The protective casing is best installed in an auger
hole and the drive point then driven inside it.
35
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Drilled Wells
Construction of a drilled well (see fig. 6, p. 38) is ordinarily ac-
complished by one of two techniques—percussion or rotary hydraulic
drilling. The selection of the method depends on the geology of the
site; the depth, desired diameter, and capacity of the well; and on the
investment and time available for construction.
Percussion (Cable Tool) Method. Drilling by the cable-tool or per-
cussion method is accomplished by raising and dropping a heavy drill
bit and stem. The impact of the bit crushes and dislodges pieces of the
formation. The reciprocating motion of the drill tools mixes the drill
cuttings with water into a slurry at the bottom of the hole. This is
periodically brought to the surface with a bailer, a 10 to 20 foot
long pipe equipped with a valve at the lower end.
Caving is prevented as drilling progresses by driving or sinking
into the ground a casing slightly larger in diameter than the bit.
When wells are drilled in hard rock, casing is usually necessary only
through the overburden of unconsolidated material. A casing may
be necessary in hard rock formations to prevent caving of beds of
softer material.
Under ordinary conditions it is not difficult to detect water-bearing
beds in cable-tool holes, since the slurry in the hole does not tend to
seal off the water-bearing formation. A sudden rise or fall in the
water level in the hole during bailing indicates that a permeable bed
has been entered. Crevices or soft streaks in hard formations are
often water-bearing. Sand, gravel, limestone, and sandstone are
generally permeable and produce the largest water yields.
Rotary Hydraulic Drilling Method. The rotary hydraulic drilling
method may be used in most formations. The essential parts of the
drilling assembly include a derrick and hoist, a revolving table through
which the drill pipe passes, a series of drill pipe sections, a cutting bit
at the lower end of the drill pipe, a pump for circulation of drilling
fluid, and a power source to drive the drill.
In the drilling operation, the bit breaks up the material as it
rotates and advances. The drilling fluid (called mud) pumped down
the drill pipe picks up the drill cuttings and carries them up the
annular space between the rotating pipe and the wall of the hole.
The mixture of mud and cuttings is discharged to a settling pit where
the cuttings drop to the bottom and mud is recirculated to the drill
pipe.
When the hole is completed, the drill pipe is withdrawn and the
casing placed. The drilling mud is usually left in place and pumped
out after the casing and screen are positioned. The annular space
between the hole wall and the casing is generally filled with cement
36
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Cold Rolled Shafting
Weight 20 to 25 Ibs.
Welded Joint
Vent Hole
Pipe -
Weight 25 to 30 Ibs.
Drive Cap
-Riser Pip*
Supporting Cable
Sand Screen
Driving Point
Falling Weight
40 to 50 Ibs.
Riser Pipe
FIGURE 5. DRIVING METHODS.
-------
Pump Unit
Sanitary Well Seal
Cobble Drain
Reinforced Concrete
Cover Slab Sloped
Away From Pump
Packer - • •. :^; ; V /
•;'; ".'..Water-Bear!ng Sand
\Screen
FIGURE 6. DRILLED WELL.
-------
grout in non-water-bearing sections but may be enlarged and filled
with gravel at the level of water-bearing strata.
When little is known concerning the geology of the area, the search
for water-bearing formations must be done carefully and deliberately
so that all possible formations are located and tested. Water-bearing
formations may be difficult to recognize by the rotary method or may
be plugged by the pressure of the mud.
Seff/ng Screens or Slotted Casings in Wells
Screens or slotted casings are installed in wells to permit sand-free
water to flow into the well and to provide support for unstable
formations to prevent caving. The size of the slot for the screen or
perforated pipe should be based on a mechanical analysis of carefully
selected samples of the water-bearing formation that is to be devel-
oped. The analysis is usually made by the screen manufacturer. If
the slot size is too large, the well may yield sand when pumped. If
the slots are too small, they may become plugged with fine material
and the well yield will be reduced. In a drilled well, the screens are
normally placed after the casing has been installed; however, in a
driven well, the screen is a part of the drive assembly and is sunk to
its final position as the well is driven.
Methods of screen installation in drilled wells include (1) the pull-
back method, (2) the open-hole method, and (3) the bail-down
method. The pull-back method of installation is one in which the
casing is drawn back to expose a well screen placed inside the casing
at the bottom of the well. In the open-hole installation the screen
attached to the casing is inserted in the uncased bottom part of the
hole when the aquifer portion of the hole remains open. When the
bail-down method is employed, the screen is placed at the bottom of
the cased hole and advanced into the water-bearing formation by
bailing the sand out from below the screen.
The pull-back method is suited to bored or drilled wells, as long as
the casing can be moved, while the open-hole method is used in some
instances with rotary drilling. The bail-down method may be used
in wells' drilled by any method where water-bearing formations
consist of sand. It is not well adapted to gravel formations.
A screen may not be required in wells tapping bedrock or tightly
cemented sediments such as sandstone or limestone.
A fourth method, adaptable primarily in rotary drilled holes, is
the wash-down method. This procedure entails the circulation of
water, by use of the mud pump, through a special self-closing bottom
upward around the screen and through the annular space between
the washpipe and the permanent casing to the surface. As material
39
647035 O—62 4
-------
is washed by jet action from below it, the well screen settles to its
desired position.
If the screen is placed after positioning of the casing, it must be
firmly sealed to the casing. This is generally done by swaging out a
lead packer attached to the top of the screen. When the pull-back
method of installation is employed, a closed bail bottom, usually pro-
vides the bottom closure; a self-closing bottom serves this purpose
when the wash-down method is used. A special plug is placed in
the bottom when the bail-down method is employed. A quantity of
lead wool or a small bag of dry cement may also be tamped into the
bottom of the screen to seal it.
Development of Weils
Before a well is put into use, it is necessary to completely remove
the silt and sand from the formation adjacent to the well screen by
one of several processes known as "development." The development
procedure unplugs the formation and produces a natural filter of
coarser and more uniform particles of high permeability surrounding
the well screen. After the development is completed, there will be
a well-graded, stabilized layer of coarse material which will entirely
surround the well screen and facilitate the flow of water in the forma-
tion into the well.
The simplest method of well development is that of surging. In this
process the silt and sand grains are agitated by a series of
rapid reversals in the direction, of flow of water and are drawn
toward the screen through larger pore openings, A well may be
surged by moving a plunger up and down in it. This action moves
the water alternately into and out of the formation. When water con-
taining fine granular material moves into the well, the particles tend
to settle to the bottom of the screen. They can be removed subsequently
by pumping or bailing.
Other methods of development are interrupted pumping, com-
pressed air, dry ice, and sometimes in consolidated material, explo-
sives when used only by experts. The method of development must be
suited to the aquifer and the type of well construction. Proper devel-
opment is necessary in many formations and under many conditions
for the completion of a successful well. Its importance should not be
overlooked.
Testing Well for Yield find Drawdown
In order that the most suitable pumping equipment can be selected,
a pumping test should be made after the well has been developed to
determine its yield and drawdown. The pumping test for yield and
40
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drawdown should include the determination of the volume of water
pumped per minute or hour, the depth to the pumping level as deter-
mined over a period of time at one or more constant rates of pump-
age, the recovery of the water level after pumping is stopped, and
the length of time the well is pumped at each rate during the test pro-
cedure. When the completed well is tested for yield and drawdown,
it is essential that it be done accurately by the use of approved measur-
ing devices and accepted methods. Additional information regard-
ing the testing of wells for drawdown or yield may be obtained from
the U.S. Geological Survey, the State or local health department, and
the manufacturers of well screens or pumping equipment.
Over a period of time, wells may fail to produce for any of these
main causes.
1. Failure or wear of the pump.
2. Declining water levels.
3. Plugged or corroded screens.
Proper analysis of the cause necessitates measuring the water level
before, during, and after pumping. To facilitate measuring the
water level, one should provide for the entrance of a tape or an electri-
cal measuring device into the well in the annular space between the
well casing and the pump columns. This can be accomplished by a
Vz~ or %-inch threaded hole in the top of the sanitary well seal. A
threaded plug should be left in the hole after the yield and drawdown
of the well are measured. The plugged hole provides suitable pro-
tection against the entrance of any pollution.
Sanitary Protection of Wells
The penetration of a water-bearing formation by a well provides
a direct route for possible contamination of the ground water.
Although there are different types of wells and well construction,
there are basic sanitary aspects which must be considered and
followed.
1. The annular space outside the casing should be filled with a
watertight cement grout or clays with similar sealing prop-
erties from the surface to a minimum of 10 feet below the
ground surface. The casing should be surrounded at the ground
surface by a 4" concrete slab extending at least 2 feet in all
directions.
2. For artesian aquifers, the casing should be sealed into the
overlying impermeable formations so as to retain, the artesian
pressure.
3. When a water-bearing formation containing water of poor
quality is penetrated, the formation should be sealed off to pre-
41
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Soft Rubber
Expanding
Gasket
Well
Casing-*.
Drop
Pipes
Drop Pipes
Weld
Drop Pipe-
Well
Casing-
Drop Pipe
Soft Rubber
Expanding
Gasket
Soft Rubber
Expanding Gasket
Well
Casing
FIGURE 7. SANITARY WELL SEALS.
vent the infiltration of water into the well and developed
aquifer.
4. A sanitary well seal should be installed at the top of the well
casing to prevent the entrance of contaminated water or other
objectionable material.
For large-diameter wells such as dug wells, it would be difficult to
provide a sanitary well seal; consequently, a reinforced concrete slab
extending at least 2 feet beyond the sides of the well should be provided
to prevent any entrance through the annular space.
Well Covers and Seals
Every well should be provided with an overlapping, watertight
cover at the top of the casing or pipesleeve to prevent contaminated
42
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water or deleterious material from entering the well. Pump or power
units with closed metal bases can be obtained and properly installed to
provide a watertight closure.
A sanitary well seal should be provided at the terminal of any well
casing. This is particularly important in wells equipped with pumps
having an open-type pedestal or base and in wells where the power
unit is not placed directly over the well, as in suction and jet pump
installations. There are several makes of sanitary well seals con-
sisting of an expanding rubber gasket between, metal plates. They
are easily installed and removed when well maintenance is necessary.
(See fig. 7, p. 42.)
If the pump is not installed immediately after well-drilling and
placement of the casing, the top of the casing should be closed with a
metal cap screwed or tack-welded into place, or covered with a sani-
tary well seal.
Every cover and pump platform should be watertight and elevated
above the adjacent existing or finished ground level. Pumproom
floors should drain to outside level. Floor surfaces should be sloped
away from the well to facilitate the rapid removal or diversion of
surface and waste water. These surfaces should be constructed of
reinforced, watertight concrete and sloped from the well casing or
sleeve to the outer edge of the slab. The slab or pumproom floor
should have a minimum thickness of 4 inches. Pumps should be
mounted on a platform or foundation when placed above the top of
the well casing. The top of the casing should be set at least 2 feet
above flash-flood level.
Disinfection of Wells
All newly constructed wells should be disinfected to neutralize con-
tamination from equipment, material, or surface drainage introduced
during construction or repair. Every well should be disinfected
promptly after construction or repair.
An effective and economical method of disinfecting wells and
appurtenances is that of using calcium hypochlorite containing
approximately 70 percent available chlorine. This chemical can
be purchased in granular form at some hardware stores, swimming
pool equipment supply outlets, or chemical supply houses.
When used in the disinfection of wells, calcium hypochlorite should
be added in sufficient amounts to provide a dosage of approximately
50 mg/1 of available chlorine in the well water. This concentration
is roughly equivalent to a mixture of 1 ounce of dry chemical per 100
gallons of water to be disinfected. Practical disinfection requires the
use of a stock solution. The stock solution may be prepared by mixing
43
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one ounce of high-test hypochlorite with 2 quarts of water. Mixing
is facilitated if a small amount of the water is first added to the gran-
ular calcium hypochlorite and stirred to a smooth watery paste free of
lumps. It should then be mixed with the remaining quantity of water.
The stock solution should be stirred thoroughly for 10 to 15 minutes
prior to allowing the inert ingredients to settle. The clearer liquid
containing the chlorine should be used and the inert material dis-
carded. Each two quarts of stock solution will provide a concentra-
tion of approximately 50 mg/1 when added to 100 gallons of water.
The solution should be prepared in a thoroughly clean utensil; the
use of metal containers should be avoided, if possible, as they are
corroded by strong chlorine solutions. Crockery, glass, or rubber-
lined containers are recommended.
Where small quantities of disinfectant are required and a scale is
not available, the material can be measured with a spoon. A heaping
tablespoonf ul of granular calcium hypochlorite weighs approximately
% ounce.
When calcium hypochlorite is not available, other sources of avail-
able chlorine such as sodium hypochlorite (12-15% of volume) can
be used. Sodium hypochlorite, which is also commonly available as
liquid household bleach with 5.25 percent available chlorine, can be
diluted with two parts of water to produce the stock solution. Two
quarts of this solution can be used for disinfecting 100 gallons of
water.
Stock solutions of chlorine in any form will deteriorate rapidy un-
less properly stored. Dark glass or plastic bottles with airtight caps
are recommended. Bottles containing solution should be kept in a
cool place and protected from direct sunlight. If proper storage facil-
ities are not available, the solution should always be prepared fresh
immediately before use. Commercially available household bleach
solutions, because of their convenience and usual reliability as to con-
centration or strength, are preferred stock solutions for disinfecting
individual water supplies.
Dug
1. After the casing or lining has been completed, follow the
procedure outlined below before placing the cover platform over the
well.
a. Remove all equipment and materials, including tools, forms,
platforms, etc. which will not form a permanent part of the
completed structure.
b. Using a stiff broom or brush, wash the interior wall of the
casing or lining with a strong solution (100 mg/1 of chlorine)
to insure thorough cleaning.
44
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2. Place the cover over the well and pour the required amount of
chlorine solution into the well through the manhole or pipesleeve
opening just before inserting the pump cylinder and drop-pipe assem-
bly. The chlorine solution should be distributed over as much of the
surface of the water as possible to obtain proper diffusion of the
chemical through the water. Diffusion of the chemical with the well
water may be facilitated by running the solution into the well through
the water hose or pipeline as the line is being alternately raised and
lowered. This method should be followed whenever possible,
3. Wash the exterior surface of the pump cylinder and drop pipe
with the chlorine solution as the assembly is being lowered into the
well.
4. After the pump has been set in position, pump water from the
well until a strong odor of chlorine is noted.
5. Allow the chlorine solution to remain in the well for not less
than 24 hours.
6. After 24 hours or more have elapsed, flush the well to remove all
traces of chlorine.
Drilled, Driven, and Bored Wells
1. When the well is being tested for yield, the testpump should
be operated until the well water is as clear and as free from turbidity
as possible,
2. After the testing equipment has been removed, slowly pour the
required amount of chlorine solution into the well just before install-
ing the permanent pumping equipment. Diffusion of the chemical
with the well water may be facilitated as previously described.
3. Wash the exterior surface of the pump cylinder and drop pipe
with chlorine solution as the assembly is being lowered into the well
4. After the pump has been set in position, operate the pump until
water discharged to waste has a distinct odor of chlorine. Repeat
this procedure a few times at 1-hour intervals to insure complete cir-
culation of the chlorine solution through the column of water in the
well and the pumping equipment.
5. Allow the chlorine solution to remain in the well for not less than
24 hours.
6, After 24 hours or more have elapsed, flush the well to remove all
traces of chlorine. The pump should be operated until water dis-
charged to waste is free from the chlorine odor.
In the case of deep wells having a high-water level, it may be neces-
sary to resort to special methods of introducing the disinfecting agent
into the well so as to insure proper diffusion of chlorine throughout
the well. The following method is suggested.
Place the granulated calcium hypochlorite in a short section of pipe
capped at both ends. A number of small holes should be drilled
45
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through each cap or into the sides of the pipe. One of the caps should
be fitted with an eye to facilitate attachment of a suitable cable. The
disinfecting agent is distributed when the pipe section is lowered or
raised throughout the depth of the water.
Flowing Artesian Wells
The water from flowing artesian wells is generally free from con-
tamination as soon as the well is completed or after it has been allowed
to flow a short time. It is therefore not generally necessary to disin-
fect flowing wells. If, however, analyses show persistent contami-
nation, the well should be thoroughly disinfected as follows.
Use a device such as the pipe described in the preceding section or
any other appropriate device by means of which a surplus supply of
disinfectant can be placed at or near the bottom of the well. The cable
supporting the device can be passed through a stuffing box at the top
of the well. After the disinfectant has been placed at or near the bot-
tom of the well, throttle down the flow sufficiently to obtain an ade-
quate concentration. When water showing an adequate disinfectant
concentration appears at the surface, close the valve completely and
keep it closed for at least 24 hours.
Chlorine Treatment of Water-Bearing Strata
Sometimes a well is encountered that does not respond to the usual
methods of disinfection. A well like this has usually been contami-
nated by water that entered under sufficient head to displace water into
the water-bearing formation. The displaced water carries contami-
nation with it. The contamination that, has been carried into the
water-bearing formation can be eliminated or reduced by forcing
chlorine into the formation. Chlorine may be introduced in a num-
ber of ways, depending on the construction of the well. In some
wells it is advisable to chlorinate the water and then add a considerable
volume of a chlorine solution in order to force the treated water into
the formation. When this procedure is followed, all chlorinated
water should have a chlorine strength of approximately 50 mg/1. In
other wells, such as the drilled well cased with standard weight cas-
ing pipe, it is entirely practicable to chlorinate the water, cap the
well, and apply a head of air. When air is alternately applied and re-
leased, a vigorous surging effect is obtained and chlorinated water
is forced into the water-bearing formation. In this procedure, the
chlorine strength of the treated water in the well will be reduced by
dilution as it mixes with the water in the water-bearing formation. It
is therefore advisable to double or triple the quantity of chlorine com-
pound to be used so as to have a chlorine strength of 100 to ISO
mg/1 in the well as the surging process is started. After treating a
46
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well in this manner, it is, of course, necessary to flush, it to remove the
excess chlorine.
Bacteriological Tests Following Disinfection
If the bacteriological examination of water samples collected after
disinfection indicates that the water is not safe for use, disinfection
should be repeated until tests show that water samples from that por-
tion of the system being disinfected are satisfactory. Samples col-
lected immediately after disinfection may not be representative of the
water served normally. Hence, if bacteriological samples are collected
immediately after disinfection, it is necessary that the sampling be
repeated several days later to check on the delivered water under nor-
mal conditions of operation and use. The water from the system
should not be used for domestic and culinary purposes until the con-
firmatory reports on the tests indicate that the water is safe for such
uses. If after repeated disinfection the water is unsatisfactory, treat;
ment of the supply is needed to provide water which always meets the
Public Health Service Drinking Water Standards. Under these con-
ditions, the supply should not be used for drinking and culinary
purposes until adequate treatment has been provided.
Abandonment of Wells
Unsealed, abandoned wells constitute a potential hazard to the
public health and welfare of the surrounding area. The sealing of
an abandoned well presents certain problems, the solution of which
involves consideration of the construction of the well and the geolog-
ical and hydrological conditions of the area. In the proper sealing of a
well, the main factors to be considered are elimination of any physical
hazard, the prevention of any possible contamination of the ground
water, the conservation and maintenance of the yield and hydrostatic
pressure of the aquifer, and the prevention of any possible contact
between desirable and undesirable waters.
The basic concept behind the proper sealing of any abandoned well
is that of restoration, as far as feasible, of the controlling geological
conditions that existed before the well was drilled or constructed. If
this restoration can be properly accomplished, an abandoned well
will not create a physical or health hazard.
When a well is to be permanently abandoned, the lower portion of
it is best protected when filled with concrete, cement grout, neat cement
or clays with sealing properties similar to those of cement. When dug
or bored wells are filled, as much of the lining should be removed as
possible so that surface water will not reach the water-bearing strata
through a porous lining or one containing cracks or fissures. When
any question arises, follow the regulations and recommendations of the
State or local health department.
47
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Abandoned wells should NEVER be used for the disposal of sewage
or other wastes.
Reconstruction of Existing Dug Wells
Existing wells used for domestic water supplies subject to contami-
nation should be reconstructed so as to insure safe water. When re-
construction is not practicable, the water supply should be treated
or a new well constructed.
Dug wells with stone or brick casings can often be rebuilt by en-
closing existing casings with concrete or by the use of a buried con-
crete slab.
Care must be exercised on entering wells because until properly
ventilated they may contain dangerous gases or lack oxygen. A
well should be opened for several hours before anyone enters it.
A lighted gasoline or carbine lantern should then be attached to a rope
and lowered to the bottom, If the lantern remains lit, it is reason-
ably safe for one to enter the well. An additional precaution is to
fasten a rope to the person entering the well and have one or more
attendants on hand to pull him to the surface at the first sign of
danger.
Improvements should be planned so that the reconstructed well
will conform as nearly as possible with the principles set forth in this
manual. If there is any doubt as to what should be done, advice
should be obtained from the State or local health department.
Special Considerations in Constructing Artesian Wells
In order that the water may be conserved and the productivity of
an artesian well improved, it is essential that the casing be sealed into
the confining stratum. Otherwise, a loss of water may occur by leak-
age into lower pressure permeable strata at higher elevations. A
flowing artesian well should be designed so that the movement of water
from the aquifer can be controlled. Water can be conserved if the ar-
tesian well is equipped with a valve or shut-off device. When the
recharge area and aquifer are large and the number of wells which
penetrate the aquifer are small, the flowing artesian well produces
a fairly steady flow of water throughout the year.
DEVELOPMENT OF SPRINGS
There are two general requirements necessary in the development of
a spring used as a source of domestic water: (1) selection of a spring
with adequate capacity to provide the required quantity or quality
of water for its intended use throughout the year, (2) protection of
48
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-Cleanout Drain
Perforated Pipe-
urface Water*
Diversion
Ditch
Fence-
PLAN
Surface Water
Diversion Ditch
i— Maximum Water Level
. /
|p / Water Stop
'
Water-Bearing Gravel
•, CJeanout Drain . ;
-' '.'••'•• '• •'':'. '/ •'• ":: FIFVATION
FIGURE 8. Spring Protection.
49
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the sanitary quality of the spring. The measures taken to develop
a spring must be tailored to its geological conditions and sources.
The features of a spring encasement are the following: (1) an
open-bottom, watertight basin intercepting the source which extends to
bedrock or a system of collection pipes and a storage tank, (2) a cover
which prevents the entrance of surface drainage or debris into the
storage tank, (3) provision for the cleanout and emptying of the tank
contents, (4) provision for overflow, and (5) a connection to the dis-
tribution system or auxiliary supply. (See fig. 8, p. 49.)
A tank is usually constructed in place with reinforced concrete of
such dimensions as to enclose or intercept as much of the spring as
possible. When a spring is located on a hillside, the downhill wall
and sides are extended to bedrock or to a depth that will insure
maintenance of an adequate water level in the tank. Supplementary
cutoff walls of concrete or impermeable clay extending laterally
from the tank may be used to assist in controlling the water table
in the locality of the tank. The lower portion of the uphill wall of
the tank can be constructed of stone, brick, or other material so placed
that water may move freely into the tank from the formation. Back-
fill of graded gravel and sand will aid in restricting movement of
fine material from the formation toward the tank.
The tank cover should be cast-in-place to insure a good fit. Forms
should be designed to allow for shrinkage of concrete and expansion
of form lumber. The cover should extend down over the top edge
of the tank at least 2 inches. The tank cover should be heavy enough
so that it cannot be dislodged by children and should be equipped for
locking.
A drain pipe with an exterior valve should be placed close to the
wall of the tank near the bottom. The pipe should extend horizon-
tally so as to clear the normal ground level at the point of discharge
by at least 6 inches. The discharge end of the pipe should be screened
to prevent the entrance of rodents and insects.
The overflow is usually placed slightly below the maximum water-
level elevation and screened. A drain apron of rock should be pro-
vided to prevent soil erosion at the point of overflow discharge.
The supply outlet from the developed spring should be located about
6 inches above the drain outlet and properly screened. Care should
be taken in casting pipes into the walls of the tank to insure good
bond with the concrete and freedom from honeycomb around the pipes.
Son/far/ Protection of Springs
Springs usually become contaminated when barnyards, sewers, septic
tanks, cesspools, or other sources of pollution are located on higher
adjacent land. In limestone formations, however, contaminated mate-
50
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rial frequently enters the water-bearing channels through sink holes
or other large openings and may be carried along with ground water
for long distances. Similarly, if material from such sources of con-
tamination finds access to the tubular channels in glacial drift, this
water may retain its contamination for long periods of time and for
long distances.
The following precautionary measures will help to insure developed
spring water of a consistently high quality.
1. Provide for the removal of surface drainage from the site. A
surface drainage ditch located at least 50 feet away on the
uphill side of the spring will prevent contaminating material
from entering the source.
2. Construct a suitable fence at least 100 feet from the water
source to prevent entry of livestock. The drainage ditch
should be inside the fence at all points uphill from the source.
3. Provide for access to the tank for maintenance, but prevent
removal of the cover by a suitable locking device.
4. Monitor the quality of the spring water with periodic checks
for contamination. A marked increase in turbidity after a
storm is a good indication that surface runoff is reaching the
spring.
Disinfection of Springs
Spring encasements should be disinfected by a procedure similar
to that used for dug wells. If the water pressure is not sufficient
to raise the water to the top of the encasement, it may be possible to
shut off the flow and thus keep the disinfectant in the encasement for
24 hours. If the flow cannot be shut off entirely, arrangements should
be made to supply disinfectant continuously for as long a period as
practicable.
INFILTRATION GALLERIES
Many recreational or other developments located in the mountains
have access to water supplies which are usually located near the head-
waters of mountain streams where the watersheds are generally heav-
ily forested and uninhabited by man. Under these conditions, con-
tamination is limited to soil bacteria and animal pollution which
reaches the streams during and following periods of runoff from the
watershed.
Some of the major problems which are encountered in operating and
maintaining these supplies are created by debris and turbidity en-
countered at the waterworks intake following spring thaws and pe-
riods of heavy rainfall. When practical, arrangements should be
made to remove this material before it reaches the intake. Experience
51
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has demonstrated that this material can be removed successfully,
especially when small volumes of water are involved, by installing
an infiltration gallery at or near the intake.
Where soil formations adjoining a stream are favorable, the water
can be intercepted by an infiltration gallery located a reasonable dis-
tance from the high-water level and a safe distance below the ground
surface. The gallery should be installed so that it will intercept the
flow from the stream after flowing through the intervening soil forma-
tions between the stream and infiltration gallery.
A typical installation generally involves the construction of an
under-drained, sand-filter trench located parallel to the stream bed and
about 10 feet from the high-water mark. The sand filter is usually
located in a trench with a minimum width of 30 inches and a depth of
about 10 feet. At the bottom of the trench, perforated or open joint
tile is laid in a bed of gravel about 12 inches in thickness with about
4 inches of graded gravel located over the top of the tile to support the
filtering material. The embedded tile is then covered with clean, coarse
sand to a minimum depth of 24 inches, and the remainder of the trench
backfilled with fairly impervious material. The collection tile is
terminated in a watertight, concrete basin from where it is diverted or
pumped to the distribution system following chlorination.
Where soil formations adjoining a stream are unfavorable for the
location of an infiltration gallery, the debris and turbidity which are
occasionally encountered in a mountain stream can be removed by
constructing a modified infiltration gallery—slow sand filter combina-
tion in the stream bed. A typical installation involves the construction
of a dam across the stream to form a natural pool or the excavation
of a pool behind the dam. The filter is installed in the pool behind
the dam by laying perforated pipe in a bed of graded gravel which is
covered by at least 24 inches of clean, coarse sand. About 24 inches
of free board should be allowed between the surface of the sand and
the dam spillway. The collection lines usually terminate in a water-
tight, concrete basin located adjacent to the upstream face of the dam
from where the water is diverted to chlorination facilities. Experience
with these units indicates that they provide satisfactory service with
limited maintenance.
52
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Part III
Surface Water
for Rural Use
The selection and use of surface water sources for individual water
supply systems require consideration of additional factors not usually
associated with ground-water sources. When small streams, open
ponds, lakes, or open reservoirs must be used as sources of water
supply, the danger of contamination and of the consequent spread of
enteric diseases such as typhoid fever and dysentery is increased. As
a rule, surface water should be used only when ground-water sources
are not available or are inadequate. Clear water is not always safe,
and the old saying that running water "purifies itself" to drinking
water quality within a stated distance is false.
The physical and bacteriological contamination of surface water,
except in sparsely settled areas, make it necessary to regard such
sources of supply as unsafe for domestic use unless reliable treatment,
including filtration and disinfection if necessary, is provided. It
should be recognized also that the treatment of surface water to insure
a constant, safe supply requires diligent attention to operation and
maintenance by the owner of the system.
When ground-water sources are limited, consideration should be
given to their development for domestic purposes only. Surface-water
sources can then provide water needed for stock and poultry watering,
gardening, firefighting, and similar purposes. Treatment of surface
water used for livestock is not generally considered essential. There
is, however, a trend to provide stock and poultry drinking water which
is free from bacterial contamination and certain chemical elements.
SOURCES OF SURFACE WATER
Principal sources of surface water which may be developed include
controlled catchments, ponds or lakes, surface streams, and irrigation
canals. Except for irrigation canals, where discharges are dependent
on irrigation activity, these sources derive water from direct precipita-
tion over the drainage area.
Because of the complexities of the hydrological, geological, and
meteorological factors affecting surface-water sources, it is reconx-
53
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mended that in planning the development of natural catchment areas
of more than a few acres, engineering advice be obtained.
In order to estimate the yield of the source, it is necessary for one to
consider the following information pertaining to the drainage area.
1. Total annual precipitation
2. Seasonal distribution of precipitation
3. Annual or monthly variations of rainfall from normal levels
4. Annual and monthly evaporation and transpiration rates
5. Soil moisture requirements and infiltration rates
6. Runoff gauge information
7. All available local experience records
Much of the required data, particularly that concerning precipita-
tion, can be obtained from publications of the United States Weather
Bureau. Essential data such as soil moisture and evapotranspiration
requirements may be obtained from local soil conservation and agri-
cultural agencies or from field tests conducted by hydrologists.
Controlled Catchments
In some areas ground water is so inaccessible or so highly mineral-
ized that it is not satisfactory for domestic use. In these cases the use
of controlled catchments and cisterns may be necessary. A properly
located and constructed controlled catchment and cistern, augmented
by a satisfactory filtration unit and adequate disinfection facilities,
will provide a safe water.
A controlled catchment is a defined surface area on which rainfall
runoff is collected. It may be a roof or a paved ground surface. The
collected water is stored in a constructed covered tank called a cistern
or reservoir. Ground-surface catchments should be fenced to prevent
unauthorized entrance by either man or animals. There should be no
possibility of the mixture of undesirable surface drainage and con-
trolled runoff. An intercepting drainage ditch around the upper edge
of the area and a raised curb around the surface will prevent the
entry of any undesirable surface drainage.
For these controlled catchments, simple guide lines to determine
water yield from rainfall totals can be established. When the con-
trolled catchment area has a smooth surface or is paved and the runoff
is collected in a cistern, water loss due to evaporation, replacement of
soil moisture deficit, and infiltration is small. As a general rule, losses
from smooth concrete or asphalt-covered ground catchments average
less than 10 percent; for shingled roofs or tar and gravel surfaces
losses should not exceed 15 percent, and for sheet metal roofs the
is negligible.
54
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150
Runoff * 0.75 Total Preciptation
1,000
2,000 3,000 4,000 5,000
Horizontal Area of Catchment, (In Square Feet)
6,000
FIGURE 9. YIELD OF IMPERVIOUS CATCHMENT AREAS.
A conservative design can be based on the assumption that the
amount of water that can be recovered for use is three-fourths of the
total annual rainfall. (See fig. 9, p. 55.)
Location. A controlled catchment may be suitably located on a
hillside near the edge of a natural bench. The catchment area can be
placed on a moderate slope above the receiving cistern.
The location of the cistern should be governed by both convenience
and quality protection. A cistern should be as close to the point of
ultimate use as practical. A cistern should not be placed closer than
50 feet from any part of a sewage-disposal installation, and should
be on higher ground.
Cisterns collecting water from roof surfaces should be located ad-
jacent to the building, but not in basements subject to flooding. They
may be placed below the surface of the ground for protection against
freezing in cold climates and to keep water temperatures low in warm
climates but should be situated on the highest ground practicable,
with the surrounding area graded to provide good drainage.
Size, The size of a cistern needed will depend on the size of the
family and the length of time between periods of heavy rainfall.
Daily water requirements can be estimated from table 1, p. 16. The
size of the catchment or roof will depend on the amount of rainfall
647035 O—62 6
55
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and the character of the surface. It is desirable to allow a safety
factor for lower than normal rainfall levels. Designing for two-thirds
of the mean annual rainfall will result usually in a catchment area of
adequate capacity.
The following example illustrates the procedure for determining
the size of the cistern and required catchment area. Assume that the
minimum drinking and culinary requirements of a family of four
persons are 100 gallons per dayl (4 persons x 25 gallons per day = 100
gallons) and that the effective period2 between rainy periods is 150
days. The volume of the cistern required will be 15,000 gallons
(100x150). This volume could be held by a cistern 10 feet deep and
15 feet square. If the annual rainfall is 50 inches, then the total
design rainfall is 13.7 inches (50x%xl50/365). In fig. 9, p.. 55, the
required catchment area is 2600 square feet.
Construction, Cisterns should be of watertight construction with
smooth interior surfaces. Manhole or other covers should be tight to
prevent the entrance of light, dust, surface water, insects, and animals.
Manhole openings should have a watertight curb with edges pro-
jecting a minimum of 4 inches above the level of the surrounding
surface. The edges of the manhole cover should overlap the curb and
project downward a minimum of 2 inches. The covers should be
provided with locks to minimize the danger of contamination and
accidents.
Provision can be made for diverting initial runoff from paved sur-
faces or roof tops before the runoff is allowed to enter the cistern,
(See fig. 10, p. 57.)
Inlet, outlet, and waste pipes should be effectively screened. Cistern
drains and waste or sewer lines should not be connected.
Underground cisterns can be built of brick or stone, although re-
inforced concrete is preferable. If used, brick or stone must be low
in permeability and laid with full Portland cement mortar joints,
Brick should be wet before laying. High quality workmanship is
required, and the use of unskilled labor for laying brick or stone is
not advisable. Two i^-inch plaster coats of 1:3 Portland cement
mortar on the interior surface will aid in providing waterproofing.
A hard impervious surface can be made by troweling the final coat
before it is fully hardened.
Fig. 10, p. 57, shows a suggested design for a cistern of reinforced
concrete. A dense concrete should be used to obtain water-tightness
and should be vibrated adequately during construction to eliminate
1 Twenty-five gallons per person per day, assuming that other uses are supplied
by water of poorer quality.
* Effective period Is the number of days between periods of rainfall during
which there Is negligible precipitation.
56
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Down Spout
from Roof
Screen
-
KOverflow
1
Valve & Box
^XXv^
_, -_
in^
V
•
t •• * i
~WL
Caulking^
Roof
Washer
Receives First
Runoff From Roof
>;j}s>i 111 if\
Faucet
z
. > •.
Maximum Water Level
Screen-
-Screened
'
i
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honeycomb. All masonry cisterns should be allowed to wet cure
properly before being used.
The procedures outlined in part V of this manual should be followed
in disinfecting the cistern with chlorine solutions. Initial and periodic
water samples should be taken to determine the bacteriological quality
of the water supply. Chlorination may be required on a continuing
basis if the bacteriological results indicate that the quality is
unsatisfactory.
Ponds or Lakes
A pond or lake should be considered as a source of water supply
only after ground-water sources and controlled catchment systems.are
found to be inadequate or unacceptable. The development of a pond
as a supply source depends on several factors: (1) the selection of a
watershed that permits only water of the highest quality to enter the
pond, (2) usage of the best water collected in the pond, (3) filtration
of the water to remove turbidity and reduce bacteria, (4) disinfection
of filtered water, (5) proper storage of the treated water, and (6)
proper maintenance of the entire water system. Local authorities
may be able to furnish advice on pond development.
The value of a pond or lake development is its ability to store water
during wet periods for use during periods of little or no rainfall.
A pond should be capable of storing a minimum of one year's supply
of water. It must be of sufficient capacity to meet water supply de-
mands during periods of low rainfall with an additional allowance
for seepage and evaporation losses. The drainage area (watershed)
should be large enough to catch sufficient water to fill the pond or lake
during wet seasons of the year.
Careful consideration of the location of the watershed and pond site
reduces the possibility of chance contamination.
The watershed should:
1. Be clean, preferably grassed.
2. Be free from barns, septic tanks, privies, and soil-absorption
fields.
3. Be effectively protected against erosion and drainage from
livestock areas.
4. Be fenced to exclude livestock.
The pond should:
1. Be not less than 8 feet deep at deepest point.
2. Be designed to have the maximum possible water storage area
over 3 feet in depth.
3. Be large enough to store at least one year's supply.
4. Be fenced to keep out livestock.
5. Be kept free of weeds, algae, and floating debris.
58
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s
3
09
1
!
a
Freeboard as specified
by Engineer
A. PLAN (Overall)
Maximum Flood Water Level
FIGURE 11. Pond.
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In many instances pond development requires the construction of
an embankment with an overflow or spillway. Assistance in design-
ing a storage pond may be available from Federal, State, or local
health agencies; the U.S. Soil Conservation Service; and in publica-
tions from the State or county agricultural, geological, or soil conserva-
tion departments. For specific conditions, engineering or geological
advice may be needed.
Intake: A pond intake must be properly located in order that it
may draw water of the highest possible quality. When the intake
is placed too close to the pond bottom, it may draw turbid water or
water containing decayed organic material. When placed too near
the pond surface, the intake system may draw floating debris, algae,
and aquatic plants. The depth at which it operates best will vary,
depending upon the season of the year and the layout of the pond.
The most desirable water is usually obtained when the intake is
located between 12 and 18 inches below the water surface. An intake
located at the deepest point of the pond makes maximum use of stored
water.
Pond intakes should be of the type illustrated in fig. 11, p. 59. This
is known as a floating intake. The intake consists of a flexible pipe
attached to a rigid conduit which passes through the pond
embankment.
In accordance with applicable specifications, gate valves should
be installed on the main line below the dam and on any branch line
to facilitate control of the rate of discharge.
Treatment: The pond water-treatment facility consists of four gen-
eral parts. (See fig. 12, p. 61.)
1. Settling Basin. The first unit is a settling basin. The purpose
of the basin is to allow the large particles of turbidity to settle. This
may be adequately accomplished in the pond. WTien this is not com-
pletely effective, a properly designed settling basin with provision
for coagulation may be needed. The turbid water is mixed with a
suitable chemical such as alum. Alum and other chemical aids speed
up the settling rate of suspended materials present in the water. This
initial process helps to reduce the turbidity of the water to be passed
through the filter.
2. Filtration Unit. After settling, the water moves to a second
compartment where it passes through a filter bed of sand and gravel.
The suspended particles which are not removed by settlement or
flocculation are now removed.
3. Clear Water Storage. After the water leaves the filter, it drains
into a clear well, cistern, or storage tank.
4. Disinfection Area. After water has settled and has been filtered
it must be disinfected. Proper disinfection is the most important
60
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Pressure Tank-
Hand
Valve
Automatic Chlonnator
Automatic Pump
Float Valve
Rei nforced Concrete Top
Hand Valve
Reinforced Concrete Top
Foot Valve
& Strai ner
Reinforced
Concrete
PUMP HOUSE
CLEAR WEI
To Water Coagulation &
Sedimentation Chamber
-Washed River Sand
Screened Through 1/8" Sieve
Purified Water to House
(Beiow Frost Line)
FIQUBE 12. Pond Water-Treatment System.
part of pond-water treatment. The continuous operation and high-
quality performance of the equipment are very important. The dif-
ferent types of equipment and processes are described in detail in
part IV. When the water is chlorinated, livestock unaccustomed to
chlorinated water may refuse to drink the water for several days.
They usually become accustomed to it within a short period of time.
Special Considerations
Bacteriological Examination: After the treatment and disinfection
equipment have been checked and are operating satisfactorily, a
bacteriological examination of a water sample should be made.
Before a sample is collected, the examining facility should be con-
tacted for its recommendations. These recommendations should
include the type of container to be used and the method and precau-
tions to take during collection, handling, and mailing. When no
other recommendations are available, follow those given in appendix B.
Water should NOT be used for drinking and culinary purposes
until the results of the bacteriological examination show the water to
be safe.
The f requency of subsequent bacteriological examinations should be
based on any breakdown or changes made in the sanitary construction
or protective measures associated with the supply. A daily deter-
-------
mination and record of the chlorine residual is recommended to
insure that proper disinfection is accomplished.
Plant Maintenance: The treatment facility should be inspected
daily. The disinfection equipment should be checked to make sure
it is operating satisfactorily. When chlorine disinfection is practiced,
the chlorinator and the supply of chlorine solution should be checked.
The water supply should be checked daily for its chlorine residual.
The water may become turbid after heavy rains and the quality may
change. Increases in the amount of chlorine and coagulates used will
then be required. The performance of the filter should be watched
closely. When the water becomes turbid or the available quantity of
water decreases, the filter should be cleaned or backwashed.
Protection from Freezing; Protection against freezing must be pro-
vided unless the plant is not operated and is drained during freezing
weather. In general, the filter and pumproom should be located in a
building that can be heated in winter. With suitable topography the
need for heat can be eliminated by placement of the pumproom and
filter underground on a hillside. Gravity drainage from the pump-
room must be possible to prevent flooding. No matter what the ar-
rangement, the filter and pumproom must be easily accessible for
maintenance and operation.
Taste and Odors: Surface water frequently develops musty or un-
desirable tastes and orders. These are generally caused by the presence
of microscopic plants called algae. There are many kinds of algae.
Some occur in long thread-like filaments that are visible as large green
masses of scum; others may be separately free-floating and entirely
invisible to the unaided eye. Some varieties may grow in great quan-
tities in the early spring, others in summer, and still others in the fall.
Tastes and odors generally result from the decay of dead algae. This
decay occurs naturally as plants pass through their life cycle. For ad-
ditional discussion see "Control of Algae" in part IV.
Tastes and odors in water can usually be satisfactorily removed by
passing the previously filtered and chlorinated surface water through
an activated carbon filter. These filters may be helpful in improving
the taste of small quantities of previously treated water used for drink-
ing or culinary purposes. They also absorb excess chlorine. Carbon
filters are commercially available, and require periodic servicing.
Carbon filters should not be expected to be a substitute for sand
filtration and disinfection. They have insufficient area to handle raw
surface water and will clog very rapidly when filtering turbid water.
Weed Control: The growth of weeds around a pond should be con-
trolled by cutting or pulling. Before weedkillers are used, the local
health department should be contacted for advice since herbicides often
contain compounds that are highly toxic to humans and animals.
62
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Algae in the pond should be controlled, particularly the blue-green
types which produce scum and objectionable odors and which, in un-
usual instances, may harm livestock. (See part IV.)
Streams
Streams receiving runoff from large uncontrolled watersheds may
be the only source of water supply. The physical and bacteriological
quality of surface water varies and may impose unusually or abnor-
mally high loads on the treatment facilities. Spring runoff from
thaws or a sudden downpour of rain may be contaminated as well as
highly turbid.
Stream intakes should be located upstream away from sewer outlets
or other sources of contamination. The water should be pumped when
the silt load is low. A low water stage usually means that the tempera-
ture of the water is higher than normal, the water is of poor chemical
quality, and that the water is diluted by waste. Maximum silt loads,
however, occur during maximum runoff. High-water stages shortly
after storms are usually the most favorable for diverting or pumping
water to storage. These conditions vary and should be determined
for the particular stream.
Irrigation Canals
If properly treated, irrigation water may be used as a source of
domestic water supply. When return irrigation (tail water) is prac-
ticed, the water may contain large concentrations of undesirable chem-
icals. Whenever water from return irrigation is used for domestic
purposes, a periodic chemical analysis should be made.
Water obtained from irrigation canals should be treated the same
as water from any other surface-water source. For additional in-
formation, see part IV.
63
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Part IV
Water Treatment
NEED AND PURPOSE
Raw waters obtained from natural sources may not be completely
satisfactory for domestic use. Surface waters may contain pathogenic
(disease-producing) organisms, suspended matter, or organic sub-
stances. Except in limestone areas, ground water is less likely to have
pathogenic organisms than surface water, but may contain undesir-
able tastes and odors or mineral impurities limiting its use or accept-
ability. Some of these objectionable characteristics may be tolerated
temporarily, but it is desirable to raise the quality of the water to the
highest possible level by suitable treatment. In those instances where
the nearly ideal water can be developed from a source, it is still ad-
visable to provide the necessary equipment for treatment to insure
safe water at all times.
The quality of a natural water constantly changes. Natural proc-
esses which affect water quality are solution, sedimentation, filtration,
aeration, sunlight, and biochemical decomposition. Natural processes
may tend to pollute and contaminate or to purify the water; however,
the natural processes of purification are not consistent or reliable.
Bacteria which are numerous in waters at or near the earth's surface
may be reduced by soil filtration, depletion of available oxygen, or
underground detention for long periods under conditions unfavorable
for bacterial growth or survival. When water flows through under-
ground fissures or channels, however, it may retain contamination over
long distances and for extended periods of time.
The false belief that flowing water purifies itself after traveling
various distances has led to unjustified feelings of security about its
safety. Under certain conditions the number of microorganisms in
flowing surface water may increase instead of decrease.
Water treatment incorporates, modifies, or supplements certain nat-
ural processes. This provides adequate assurance that the water is
free from pathogenic organisms or other undesirable materials or
chemicals. Water treatment may condition or reduce to acceptable
levels any chemicals or aesthetically objectionable impurities which
may be present in the water.
64
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Some of the natural treatment processes and man-made adaptations
to improve and condition water are discussed in the following sections.
SEDIMENTATION
Sedimentation is a process of gravity settling and deposition of
comparatively heavy suspended material in water.
This settling action can be accomplished in a quiescent pond or
properly constructed tank or basin. The inlet of the tank should be
arranged so that the incoming water containing suspended matter is
distributed uniformly across the entire width as the water flows to the
outlet located at the opposite end. Baffles are usually constructed to
reduce high local velocities and short circuiting of the water. The
cleaning and repairing of an installation can be facilitated by the use
of a tank designed with two separated sections, each of which may
be used independently.
COAGULATION
Coagulation is the process of forming flocculent particles in a liquid
by the addition of a chemical. Coagulation is achieved by adding
to the water a chemical such as alum (hydrated aluminum sulfate).
The chemical is mixed with the turbid water and then allowed to
remain quiet. The suspended particles will combine physically and
form a floe. The floe or larger particles will settle to the bottom of
the basin. This may be done in a separate mixing tank or in the same
tank. Some colors can be removed from water by using proper coag-
ulation techniques. Competent engineering advice, however, should
be obtained on specific coagulation problems.
FILTRATION
Filtration is the process of removing suspended matter from water
as it passes through beds of porous material. The degree of removal
depends on the character and size of the filter media, the thickness of
the coat or bed, and the size and quantity of the suspended solids.
Since bacteria can travel long distances through granular materials,
filters should not be relied upon to produce bacteriologically safe
water, even though they may greatly improve the quality. When a
water source contains a large amount of turbidity, a large portion of
it can first be removed by sedimentation. This action will reduce the
load placed on the filters.
Types of filters which may be used include:
Slow sand filters—Water passes slowly through beds of fine
sand at rates less than 0.05 gallons per minute per square foot
of filter area.
65
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Pressure sand filters—Water is applied at a rate at or above 2
gallons per minute per square foot of filter area with provisions
made for frequent backwashing of the filters.
Diatomaceous earth filters—Suspended solids are removed by
passing the water through a layer of diatomaceous filter media
supported by a rigid base septum at rates approximately that
of pressure sand filters.
Porous stone, ceramic, or unglazed porcelain filters (Pasteur
filters)—These are small household filters which are attached
to faucets.
Properly constructed sand filters require a minimum of maintenance
and can be easily adapted to individual water systems. The length of
time between cleaning will vary from a day to a week or month; the
length of the interval depends upon the turbidity of the water. After
an interval it is necessary to clean the filter by removing approxi-
mately one inch of sand from the surface of the filter and either dis-
carding it or stockpiling it for subsequent washing and re-use. This
removal will necessitate the periodic addition of new or washed sand.
Sand for slow sand filters should consist of hard, durable grains free
from clay, loam, dirt, and organic matter. It should have a sieve
analysis which falls within the range of values shown in table 5.
Table 5.—Recommended mechanical an of y si* of slow sancf filter media
Material passing sieve
(percent)
99
90-97
75-90
60-80
U.S. sieve
No.
4
12
16
20
Material passing sieve
(percent)
33-55
17-35
4-10
1
U.S. sieve
No.
30
40
60
100
Sands with an effective size of 0.20 to 0.40 millimeters are satis-
factory. The uniformity coefficient should be between 2.0 and 3.0.
For best results the rate of filtration for a slow sand filter should
be between 25 to 75 gallons per day per square foot of filter bed sur-
face. The amount of water which flows through the filter bed can
be adjusted by a valve placed on the influent line.
Eapid sand filtration is not usually desirable for small individual
water supplies because of the necessary controls and additional atten-
tion required to obtain satisfactory results. When adequate operation
and supervision are provided, pressure sand filtration can be used
successfully.
66
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Diatomaceous earth filters, which require periodic attention, are of
two types—vacuum or pressure. These filters are effective when
properly operated and maintained.
The possibility must be considered that dirty stone or ceramic faucet
filters may attract bacteria and provide a place for their multiplica-
tion or that these filters may develop hairline cracks. For these
reasons, small household faucet filters cannot be depended upon to
remove pathogenic bacteria, and their use is not recommended for
producing bacteriologically safe water.
Small pad, spool, or wad coarse filters may be useful for low-capac-
ity, coarse filtration for removal of large suspended particles only.
Proper disinfection of water before consumption provides assurance
that it is safe.
DISINFECTION
The most important water treatment process is disinfection. Dis-
infection is necessary to destroy all pathogenic bacteria or other
harmful organisms present in the drinking water. After disinfection,
the water must be kept in suitable tanks or other storage facilities to
prevent recontamination.
Chemical Disinfection
The desirable properties for a chemical disinfectant include high
germicidal power, stability, solubility, nontoxicity to man or animals,
economy, dependability, residual effect, ease of use and measurement,
and availability.
Chlorine Disinfection
Compounds of chlorine most satisfactorily comply with the desirable
properties of a chemical disinfectant; therefore chlorine, which is an
oxidizing agent, is a commonly used water disinfectant.
The amount of chlorine necessary to provide adequate protection
must satisfy the chlorine demand of organic or other oxidizable mate-
rial in the water and provide a residual chlorine concentration which
will insure proper disinfection after a specified contact time.
In general, and within limits, the primary factors which determine
the bactericidal efficiency of chlorine are as follows.
1. Free chlorine residual—the higher the residual, the more effec-
tive the disinfection and the faster the disinfection rate.
2. Contact time between the organism and the disinfectant
agent—the longer the time, the more effective the disinfection.
3. Temperature of the water in which contact is made—the lower
the temperature, the less effective the disinfection.
4. The pH of the water in which contact is made—the higher the
pH, the less effective the disinfection.
67
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For example, when a high pH and low temperature combination is
encountered in a water, either the concentration of chlorine or the
contact time must be increased. Likewise, chlorine residual will need
to be increased if sufficient contact time is not available in the distri-
bution system before the water reaches the first user.
Chlorine Compounds and Solutions
Compounds of chlorine such as sodium or calcium hypochlorite have
excellent disinfecting properties. In small water systems these chlo-
rine compounds are usually added to the water in a solution form.
One of the most commonly used forms of chlorine is calcium hy-
pochlorite. It is commercially available in the form of soluble pow-
der or tablets. These compounds are classed as high-test hypochlo-
rites and contain 65 to 75 percent available chlorine by weight.
Packed in cans or drums, these compounds are stable and will not
deteriorate if properly stored and handled.
Prepared sodium hypochlorite solution is available locally through
chemical or swimming pool equipment suppliers. The most common
type is household chlorine bleach which has a strength of approxi-
mately 5 percent available chlorine by weight. Other sodium hypo-
chlorite solutions vary in strength from 3 to 15 percent available
chlorine by weight, and are reasonably stable when stored in a cool,
dark place. These solutions are diluted with potable water to obtain
the desired solution strength to be fed into the system.
When hypochlorite powders are used, fresh chlorine solutions should
be prepared at frequent intervals because the strength of chlorine
solutions deteriorates gradually after preparation. The container
or vessel used for preparation, storage, or distribution of the chlorine
solution should be resistant to corrosion and light. Suitable materials
include glass, plastic, crockery, or rubber-lined metal containers.
Hypochlorite solutions as used in individual water supply systems
are used either in full solution strength or are diluted to solution
strength suited to the feeding equipment and the rate of water flow.
In preparing these solutions, one must take into account the chlorine
content of the concentrated solution. For example, if 5 gallons of 2
percent solution are to be prepared with a high-test calcium hypochlo-
rite powder or tablet containing 70 percent available chlorine, the high-
test hypochlorite would weigh 1.2 pounds.
Pounds of compound required=
% strength gallons solution
of solution required x ®**
% available chlorine in compound
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Expressed in another way 1.2 pounds of high-test hypochlorite with
70 percent available chlorine would be added to 5 gallons of water to
produce a 2 percent chlorine solution.
Disinfection Terminology
The chlorine content of water is measured in parts per million (ppm)
or more recently referred to in milligrams per liter (mg/1). One mg/1
is equivalent to one milligram in one liter of water. When disinfec-
tion is properly accomplished, the following steps are involved.
1. Chlorine Feed or Dosage: The actual amount in mg/1 fed
into the water system by feeder or automatic dosing apparatus
is the chlorine feed or dosage.
2. Chlorine Demand: The chlorine fed into the water which com-
bines with the impurities rather than that which is available
for disinfection action is commonly called the chlorine demand
of the water. Free chlorine is an active oxidizing agent, and
combines readily with organic impurities present in the water.
In addition, certain minerals, slimes, or chemicals may remove
a portion of the chlorine fed into the water.
3. Chlorine Residual: The chlorine residual is the chlorine pres-
ent in the water after the chlorine demand has been satisfied.
This chlorine protects against any chance contamination which
may accidentally enter the water system. The chlorine resid-
ual is extremely important in its relation to contact time and
speed of disinfection. Chlorine residual is measured at the
first point in the distribution system where water is drawn for
consumption. The chlorinator should be adjusted to provide
the chlorine residual strength necessary for disinfection within
the contact time available.
The above may be summarized as follows.
Chlorine Feed ™ i • ™ i •
Chlorine , Chlorine
or minus _. , equals _ ., .
• Demand Residual
Dosage
4. Chlorine Contact Time: The chlorine contact time is the period
of time that elapses between the time when the chlorine is
added to the water and the time when that particular water is
used. As a disinfectant, chlorine requires time in which to
properly disinfect. The minimum required time depends on
(1) the type of chlorine residual available—free chlorine is far
more fast-acting; (2) the strength of residual present at the
end of the contact time—higher residual indicates fast action;
(3) the pH of the water—the higher the pH, the longer the
time required; (4) water temperature—the lower the temper-
ature, the longer contact time required.
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Deternwnation of Chlorine Residual
Residual chlorine can exist in water as a chlorine compound of
organic matter and ammonia or as both combined and free available
chlorine residual. When present as a chlorine compound, it is called
combined available chlorine residual, as free chlorine it is known as
free available chlorine residual, and as both combined and free avail-
able chlorine it is called total available chlorine residual. Thus,
"sufficient chlorine" is that amount required to produce a desired resid-
ual after a definite contact period, whether combined, free, or total.
With the development of the orthotolidine-arsenite test about 1939,
the practice of free residual chlorination became widespread. This
practice consists of adding enough chlorine to produce a residual con-
sisting almost entirely of free available chlorine. The orthotolidine
arsenite (OTA) test, generally used as a laboratory control aid, dis-
tinguishes and measures quantitatively the combined and the free
available chlorine residuals. Because of its many advantages, includ-
ing ease of control, the practice of free residual chlorination is recom-
mended for individual water supply systems.
Residual Chlorine
When orthotolidine reagent is added to water containing chlorine, a
greenish-yellow color develops, the intensity of which is proportional
to the amount of residual chlorine present. Free available residual
chlorine reacts with orthotolidine practically instantaneously, requir-
ing less than 15 seconds for development of the color. Combined avail-
able residual chlorine reacts with orthotolidine relatively slowly,
requiring 5 minutes at 70° F. for full color development. Thus, the
presence or absence of an immediate or flash color indicates the
presence or absence of free available chlorine residual. This flash
color can be determined quantitatively if a weak reducing agent, such
as sodium arsenite, is added to the sample less than 15 seconds after the
addition of orthotolidine. The sodium arsenite neutralizes the com-
bined chlorine before it can react with orthotolidine reagent. The flash
color is not affected by the sodium arsenite reagent and can be read by
comparison with permanent standards at any time within 5 minutes.
Commercially available residual chlorine test kits are inexpensive
and should be used wherever chlorine disinfection is practiced.
Complete, detailed instructions are given with each test kit. For
those who wish to obtain further information concerning the test, a
description is included in Standard Methods for the Examinatwn of
Water and Wastewater.
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Chfor/nation Equipment
Hypochlorinators
Hypochlorinators pump or inject a chlorine solution into the water.
When they are properly maintained, hypochlorinators provide a re-
liable method for applying chlorine to disinfect water.
Types of hypochlorinators include positive displacement feeders,
aspirator feeders, suction feeders, and tablet hypochlorinators.
Positive Displacement Feeders. A common type of positive dis-
placement hypochlorinator is one which uses a piston or diaphram
pump to inject the solution. This type of equipment, which is adjust-
able during operation, can be designed to give reliable and accurate
feed rates. When electricity is available, the stopping and starting
of the hypochlorinator can be synchronized with the pumping unit.
A hypochlorinator of this kind can be used with any water system;
however, it is especially desirable in systems where water pressure is
low and fluctuating.
Aspirator Feeders. The aspirator feeder operates on a simple
hydraulic principle that employs the use of the vacuum created when
water flows either through a venturi tube or perpendicular to a nozzle.
The vacuum created draws the chlorine solution from a container into
the chlorinator unit where it is mixed with water passing through the
unit, and the solution is then injected into the water system. In most
cases, the water inlet line to the chlorinator is connected to receive
water from the discharge side of the water pump, with the chlorine
solution being injected back into the suction side of the same pump.
The chlorinator operates only when the pump is operating. Solution
flow rate is regulated by means of a control valve, though pressure
variations may cause changes in the feed rate.
Suction Feeders. One type of suction feeder consists of a single
line that runs from the chlorine solution container through the chlo-
rinator unit and connects to the suction side of the pump. The
chlorine solution is pulled from the container by suction created by
the operating water pump.
Another type of suction feeder operates on the syphon principle,
with the chlorine solution being introduced directly into the well.
This type also consists of a single line, but the line terminates in the
well below the water surface instead of the influent side of the water
pump. When the pump is operating, the well drawdown creates a
suction in the feeder line and the chlorine solution is pulled from the
container and into the well by a syphoning action.
In each of these units, the solution flow rate is regulated by means
of a control valve and the chlorinators operate only when the pump
is operating.
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Tablet Hypochlorinators. The tablet hypochlorinating unit con-
sists of a special pot feeder containing calcium hypochlorite tablets.
Accurately controlled by means of a flow meter, small jets of feed
water are injected into the lower portion of the tablet bed. The slow
dissolution of the tablets provides a contmuousysource of fresh hypo-
chlorite solution. This unit controls the chlorine solution. This
type of chlorinator is used when electricity is not available, but re-
quires adequate maintenance for efficient operation. It can operate
where the water pressure is low.
Gaseous Feed Chlorinators.
In installations where large quantities of water are treated, chlorine
gas in pressure cylinders may be used as the disinfectant. The high
cost of this type of chlorination equipment and the safety precautions
necessary to guard against accidents do not usually justify its use in
individual water supply systems.
Solution Supply Monitor
Sensing units which can be placed in solution containers to sound
a warning alarm when the solution goes below a predetermined level
are commercially available. This equipment can also be connected to
the pump, which will automatically shut off the pump and activate a
warning bell. On such a signal, the operator will be required to re-
fill the solution container and take necessary steps to insure proper
disinfection.
Sup ercMor/n at/on—Dechlorination
The terms superchlorination and dechlorination were first proposed
by Sir Alexander Houston in 1919. These terms were used to indicate
a process that would provide water purification and eliminate taste
and odor in water by using amounts of chlorine greatly in excess of
levels needed to meet the chlorine demand. Subsequent removal of
the excess chlorine is also a requirement in the process.
Superchlorination. An excessive amount of chlorine is used to
quickly destroy the harmful organisms which may be present in water.
As has been previously shown, chlorination is dependent upon several
factors. If an excessive amount of chlorine is used, a free chlorine
residual will be present. When the quantity of chlorine is increased,
disinfection is faster and the amount of contact time required to insure
safe water is decreased.
Decldorwctfion. The dechlorination process may be described as the
partial or complete reduction of any chlorine present in the water.
When dechlorination is provided in conjunction with proper super-
chlorination, the water will be both properly disinfected and accept-
able to the consumer for domestic or culinary uses.
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Dechlorination can be accomplished in individual water systems by
the use of activated carbon (dechlorinating) filters. Chemical dechlo-
rination by reducing agents such as sulphur dioxide or sodium thiosul-
fate can be used for batch dechlorination. Sodium thiosulfate is also
used to dechlorinate water samples prior to submission for bacterio-
logical examination.
A small portion of free available chlorine can be liberated from
a water supply by aeration. Aeration may be reasonably effective at
low pH levels but at higher pH levels it will have a limited effective-
ness. In addition to the difficulties with respect to the pH level, the
need for pumping equipment and the possibility of chance contamina-
tion by organisms present in the air make dechlorination by aeration
a poor method for general use.
Chlorination Control
The maintenance of a proper chlorine residual in a water supply sys-
tem will effectively destroy waterborne microorganisms. Experience
over many years with chlorine supports its continued use as the most
practical and effective chemical disinfectant for water supplies.
As indicated previously, several factors pertaining to a water sup-
ply system have a direct bearing on the effectiveness of chlorine. Be-
cause of these variable factors, it is not possible to suggest rigid
standards of chlorine disinfection applicable to all water supply
systems. It is considered desirable, however, to suggest the following
practice in this regard for the guidance of persons responsible for
water supply operation and maintenance.
Simple Chlorination
Unless bacteriological or other tests indicate the need for maintain-
ing higher minimum concentrations of free residual chlorine, at least
0.2 mg/1 of free residual chlorine should be in contact with the treated
water for not less than 20 minutes before the water reaches the first
user beyond the point of chlorine application. It is considered desir-
able to maintain a detectable free chlorine residual at distant points in
the distribution system when using simple chlorination; however, the
water can be properly disinfected if a minimum contact time of 20
minutes is assured.
Superchlorination—Dechlorination
Recent studies indicate that it is difficult in small water supply sys-
tems to obtain adequate contact time between the chlorine and the
water being treated to insure that proper disinfection is accomplished.
In many small systems sudden increased demands of water use and
the relatively short distance between the point of chlorine applica-
tion and the first water tap do not allow sufficient contact time for the
simple chlorination procedures just described.
-------
A method known as superchlorination-dechlorination is suggested
for use in overcoming and simplifying the problem of insufficient con-
tact time in such water systems. By this method chlorine is added to
the water in increased amounts (superchlorination) to provide a mini-
mum chlorine residual of 3.0 mg/1 for a minimum contact period of
five minutes. Removal of the excess chlorine (dechlorination) fol-
lows to eliminate objectionable chlorine tastes. Dechlorination equip-
ment is commercially available.
Records
Adequate control is also dependent on the maintenance of accurate
operating records of the chlorination process. The record should
serve as an indicator that proper chlorination is being accomplished
and as a guide in improving operations. The record should show the
amount of water treated, amount of chlorine used, setting of the
chlorinator, time and location of tests, and results of chlorine residual
determinations. This information should be kept current and posted
near the chlorinator.
He of Treatment
Under controlled conditions water may be adequately disinfected
by heat. The success in killing pathogenic organisms in milk by pas-
teurizing at temperatures of 161° Fahrenheit (F) for 15 seconds, or
145° F. for 30 minutes has been demonstrated to be an adequate stand-
ard for similar heat disinfection of water. A water pasteurizer has
been developed that is easy to operate and on certain waters requires
minimum maintenance.1 This equipment can be provided with auto-
matic controls which will insure that the unit furnishes a constant
supply of potable water. The degree of contamination of the water
may require that filtration precede pasteurization.
Of her Methods and Materials for Water Disinfection
A number of other materials and methods are used for disinfecting
water. Some of these are as follows:
1. Organic chlorine-yielding compounds
2. Bromine
3. Iodine and iodine-yielding organics
4. Ozone
5. Hydrogen peroxide and peroxide-generating compounds
6. Silver
7. Nontoxic organic acids
1 Melvin Goldstein, L. J. McCabe, Jr., Richard L. Woodward, "Continuous-Flow
Water Pasteurizer for Small Supplies." Journal of American Water Works
Association, Vol. 52 (February 1960) p. 247.
74
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8. Lime and mild alkaline agents
9. Ultraviolet radiation
10. Supersonic cavitation
Some of these are old processes on which detailed studies have been
made; others are relatively new. Current information states that
these methods are either impractical, expensive, or have other limita-
tions. In view of this information, disinfection methods other than
the use of chlorine or heat are not presently recommended for small
or individual water supply systems.
When a question of specific application arises, the recommenda-
tions of the State or local health department should be followed.
CONDITIONING
Iron and/or Manganese
The presence of iron and/or manganese in water creates a problem
common to many individual water supply systems. When both are
present beyond acceptable U.S. Public Health Service Drinking Water
Standards, special attention should be given. Their removal or elim-
ination depends somewhat on type and quantity, and this influences
the procedure and possibly the equipment to be used.
Well water is usually clear and colorless when drawn from the
faucet or tap. When water containing colorless, dissolved iron
(usually ferrous bicarbonate) is allowed to stand in a cooking con-
tainer or comes in contact with a sink or bathtub, the iron combines
with oxygen from the air to form a reddish-brown precipitate com-
monly called rust. Manganese acts in a similar manner, but forms
a brownish-black precipitate.
These impurities can impart a metallic taste to the water or to any
food in whose preparation such a supply is used. Deposits of iron
and manganese produce rusty or brown stains on plumbing fixtures,
fabrics, dishes, or utensils. The use of soaps or detergents will not
remove these stains, and bleaches and alkaline builders can intensify
the staining process. After a prolonged period, iron deposits can build
up in pressure tanks, water heaters, and pipelines. This build-up re-
duces the available quantity and pressure of the water supply.
Iron and manganese can be removed by a combination of automatic
chlorination and fine filtration. The chlorine chemically oxidizes the
iron (forming a precipitate), kills iron bacteria, and eliminates any
disease bacteria which may be present. The fine filter then removes the
iron precipitate. Some filters may dechlorinate also. This chlorina-
tion-filtration method provides complete correction of the iron prob-
lems and assures disinfection as well.
Insoluble iron and iron bacteria will intensely "foul" the mineral
75
647035i
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bed and the valving of a water softener. It is best, therefore, to re-
move iron and manganese before the water reaches the softener.
When a backwash filter medium is used it is essential that an ade-
quate quantity of water at sufficient pressure be provided for removing
the iron precipitate.
Iron Bacteria
Under certain conditions the removal of iron compounds from a
water supply may be complicated by the presence of iron bacteria.
These bacteria multiply in water when little or no dissolved oxygen
is present. They are sometimes called iron-consuming bacteria because
they consume iron to support their life processes and hence cause
pitting of iron pipe, tanks, pumps, and fixtures.
A slimy, rust-colored mass on the interior surfaces of flush tanks
or water closets indicates the presence of iron bacteria.
Iron bacteria can reduce the carrying capacity of water pipes by
increasing f rictional losses. They may impart an unpleasant taste and
odor to the water or discolor and spot fabrics, plumbing fixtures, and
clog pumps. A detectable slime also builds up on any surface with
which the water containing these organisms comes in contact. Iron
bacteria may be concentrated in a specific location and may periodically
break loose and appear at the faucet in detectable amounts of rust.
Iron-removal filters or water softeners can remove iron bacteria;
however, they often become clogged and fouled because of the slime
buildup. A disinfecting solution such as chlorine bleach should be
injected into the water to control the growth of iron bacteria. Such
a solution causes a chemical reaction which allows an iron precipitate
to form. This precipitate can be removed with a suitable fine filter.
Softening
Water softening is a process for the removal of the minerals, pri-
marily calcium and magnesium, which cause hardness. These ele-
ments are usually present in compound form as bicarbonates, sulfates
or chlorides.
Softening of hard water is desirable if:
1. Large quantities of soap are needed to produce a lather.
2. Hard scale is formed on cooking utensils or laundry basins.
3. Hard, chalklike formations coat the interiors of piping or
water tanks.
4. Heat transfer efficiency through the walls of the heating
element or exchange unit of the water tank is reduced.
The build-up of scale will cause an appreciable reduction in pipe
capacities and pressures. The appearance of excessive scale from
hard waters will also be aesthetically objectionable.
76
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Water may be softened by either the ion exchange or the lime-soda
ash process.
Ion Exchange
The ion exchange process causes a replacement of the calcium or
magnesium ions by sodium ions. The process takes place when the
hard water containing calcium or magnesium compounds comes in
contact with an exchange medium. The materials used in the process
of ion exchange are insoluble, granular materials that possess a unique
property of exchange. Exchange material may be classed as follows:
glauconite (or greensand); precipitated synthetic, organic (carbona-
ceous) , and synthetic resins; or gel zeolites. The last two are the most
commonly used for domestic purposes.
The type of ion exchange material used is determined by the type
of water treatment required. For example, when a sodium zeolite is
used to soften water by exchanging the sodium ion for calcium and
magnesium ions in the hard water, the zeolite sodium ions eventually
become of insufficient quantity to effect the exchange. After a certain
period of time determined by the exchange rate, the exchange ma-
terial must be regenerated. The sodium ion is restored to the zeolite
by passing a salt (NaCl) or brine solution through the bed. The salt
solution used must contain the same type of ions which were displaced
by the calcium and magnesium. The solution causes a reversal which
restores the exchange material to its original condition.
The type of regenerating material or solution which must be used
depends upon the type of exchange material in the filter.
The ion exchange method of softening water is relatively simple
and can be easily adapted to the small or individual water supply
system. Only a portion of the hard water needs to be passed through
the softening process because the exchange process produces water of
zero hardness. The processed water can then be mixed with the hard
water in proportions to produce a final water with a hardness between
50 to 80 mg/1. Watere with a turbidity of more than 10 units should
be properly treated to increase the effectiveness and the efficiency of
the softening process.
Ion exchange softeners are commercially available for individual
water systems. Their capacities range from about 5,000 to 32,000
grains per cubic foot of exchange material. Water softeners should
be installed only by responsible persons in strict accordance with the
instructions from the manufacturer and applicable codes. The ma-
terials and workmanship should be guaranteed for a specified period
of time. First consideration in securing ion exchange water-softening
equipment should be given to those companies providing responsible
servicing dealers permanently located within a reasonable distance
from the water supply system.
77
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Lime-Soda Ash Process
The use of the lime-soda ash process or the addition of other
chemicals is not practical for a small water supply system. Water
used for laundry purposes, however, may be softened at the time of
use by the addition of certain chemicals such as borax, washing soda,
trisodium phosphate, or ammonia. Commercial softening or water
conditioning compounds of unknown composition should NOT be
used in water intended for drinking or cooking until the advice of
the State or local health department is obtained regarding their
safety.
F/uorfdafion
The presence of trace quantities of fluorine in the diet has been
found beneficial in reducing dental caries in children and young
adults. Water is currently an economical medium through which
these trace quantities can be assimilated through body processes into
the enamel of the teeth.
Equipment for fluoridating even the smallest home water supplies
has been developed and used for several years. It is recommended
however that the installer maintain the home fluoridator and test
the treated water for fluoride level. It is an economical and reliable
means of providing fluoridated water if the operation and mainte-
nance of the fluoridating equipment are combined with other home
water supply services, i.e., softening, iron removal, chlorination, and
the like. Chlorination can be accomplished with the same feeder by
combining a hypochlorite with a fluoride solution.
When a question of specific application arises, the recommendations
of the State or local health department should be followed.
Tastes and Odors
Tastes and odors present in an individual water supply system fall
into two general classes—natural and man-made. Some natural
causes may be traced to the presence of or contact of water with algae,
leaves, grass, decaying vegetation, dissolved gases, and slime-forming
organisms. Some of the man-made causes of taste and odor may be
attributed to the presence of chemicals or sewage.
Depending upon the cause, taste and odor can be removed or
reduced by aeration or by treatment with activated carbon, copper
sulf ate, or an oxidizing agent such as chlorine.
Aeration is exposure of as much water surface as possible to the air.
It is described in the section entitled "Aeration."
The activated carbon treatment consists of passing the water to be
treated through granular or powdered carbon which attracts to itself
large quantities of dissolved gases, liquids, and finely divided solids.
76
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It is therefore extremely effective in taste and odor control. Activated
carbon can be used in carbon filters commercially available from the
manufacturers or producers of water-conditioning or treatment
equipment. The recommendations included with the filter should
be followed.
Copper Sulfate. The most frequent source of taste and odors in
an individual water supply system is algae. These minute plants
produce certain biological by-products which cause taste and odors
in the water. When they are present in a water supply, their growth
can be controlled with copper sulfate as described in the section deal-
ing with "Algae Control."
Because algae and other chlorophyl-containing plants need sun-
light to grow, the storage of water in covered reservoirs inhibits their
growth.
Chlorine. Chlorine is an effective agent in reducing tastes and
odors present in water. The process used for the reduction of tastes
and odors is the same as described in the section dealing with "Super-
chlorination-Dechlorination."
Hydrogen Sulfide
Water having a "rotten egg" odor indicates the presence of hydro-
gen sulfide and is commonly referred to as sulfur water. In addition
to its objectionable odor, sulfur water may cause a black stain on
plumbing fixtures. Hydrogen sulfide is very corrosive to common
metals and will react with iron, copper, or silver to form the sulfides
of these metals.
Hydrogen sulfide can be removed by aeration or by a combination
oxidization-filtration process. A simple iron-removal filter will also
do a good job of removing this objectionable compound when small
amounts are involved.
Corrosion Control
The control of corrosion is important not only to continuous and
efficient operation of the individual water system but also to delivery
of properly conditioned water for domestic uses. Whenever corrosion
is minimized there is an appreciable reduction in the maintenance
and possible replacement of water pipes, water heaters, or other
metallic appurtenances of the system.
Corrosion is commonly defined as an electrochemical reaction in
which metal deteriorates or is destroyed when in contact with elements
of its environment such as air, water, or soil. Whenever this reaction
occurs there is a flow of electric current from the corroding portion of
the metal towards the electrolyte or conductor of electricity, such as
water or soil. The point at which current flows from the metal into
79
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the electrolyte is called the "anode" and the point at which current
flows away from the electrolyte is called the "cathode." Any char-
acteristic of the water which tends to allow or increase the rate of
this electrical current will increase the rate of corrosion. The impor-
tant characteristics of a water that affect its corrosiveness include
the following.
1. Acidity—a measure of hydrogen ion concentration as measured
by pH. Water with acidity or low alkalinity has a tendency to be
corrosive.
2. Conductivity—a measure of the amount of dissolved mineral
salts. An increase in conductivity promotes flow of electrical current
and increases the rate of corrosion.
3. Oxygen content—amount dissolve«Hn water promotes corrosion
by destroying the thin protective hydrogen film which is present on
the surface of metals immersed in water.
4. Carbon dioxide—a weak carbonic acid which tends to attack
metallic surfaces.
5. Water temperatures—the corrosion rate increases with water
temperature.
Corrosion and Scale Relationship
Corrosion and scale are associated problems, but their effect and
cause should not be confused. The essential effect of corrosion is to
destroy metal; scale, on the other hand, tends to clog open sections
and line surfaces with deposits. The products of corrosion often
contribute to scale formation and aggravate the problem of its
treatment.
Prevention of Corrosion
When corrosion is caused by the acidity of the water supply it can
be effectively controlled by installing an acid neutralizer ahead of a
water softener. Another method of controlling corrosion is that of
feeding small amounts of commercially available film-forming ma-
terials such as polyphosphates or silicates. Other methods for con-
trolling corrosion are the installation of dielectric or insulating unions,
the reduction of water temperature, reduction of velocities and pres-
sures, removal of oxygen or acid constituents, and chemical treatment
to decrease the acidity.
pH Correction or Neutralizing Solution
The pH of water may be increased by feeding a neutralizing solu-
tion so that it no longer attacks parts of the water system or con-
tributes to electrolytic corrosion. Neutralizing solutions may be pre-
pared by mixing soda ash (58% light grade) with water—3 pounds
soda ash to 4 gallons of water. This solution may be fed into the
water supply with feeders as described under "Chlorination," and may
80
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be mixed with chlorine solutions to accomplish both pH correction
and disinfection with the same equipment. Soda ash is available at
chemical supply houses.
Because of the wide variety of factors which may create a corrosion
problem, remedial measures should be carefully selected to meet the
needs of the individual water supply system.
Afgae Control
Algae are blue-green, single-cell plant growths which may produce
scum and objectionable odors in stored waters. In exceptional cases,
cattle have been killed by the consumption of certain species of algae.
These growths can be controlled by treating the water with copper
sulfate (blue stone) or, when feasible, by covering the storage unit to
exclude sunlight.
The amount of the copper sulfate dosage varies with the particular
species of organism involved. A dose of 0.3 milligrams per liter,2
however, will generally control all but a few of the growths likely to
cause trouble in drinking water. For certain species of fish, partic-
ularly those of the trout family, this dosage may be poisonous. The
approximate doses of copper sulfate in milligrams per liter which
should not be exceeded to avoid killing various kinds of fish are given
in table 6, p. 81.
TobU 6.—Approximate maximum toforanc* llmttt of ver/otr* flttt fo copper xutfalf
Kind of fi8h
Trout
Cflrp - . - -
Suckers -- -
Pickerel
Goldfish
Sunfi sh
Black Bass
Copper sulfate
(milligrams per
liter)
0.15
0.30
0.30
0.40
0. 40
0.50
0,70
L20
2.00
Pounds per
million gallons
1.2
2.5
2.5
3.5
3.5
4.0
6.0
10.0
17.0
In small reservoirs or ponds the required dose of copper sulfate
can be dissolved in water and introduced by a sprinkling can. In
large ponds or reservoirs copper sulfate may be tied in a clean gunny
sack and dragged through the water from a boat in lanes 10 to 20 feet
apart until the copper sulfate is completely dissolved.
" 0.3 mg/1 is equivalent to about 2.5 pounds of copper sultate per million gallons
or 1 ounce In 25,000 gallons.
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The span of time over which a treatment will be effective will vary,
depending upon sunshine, reseeding, and local conditions. Several
treatments per season are generally required. Some municipalities
treat open distributing reservoirs as often as twice a month in order
to avoid unexpected blooms of algae and the accompanying taste and
odor problem.
Control will be easier and more effective if the treatment is
done before the algae bloom or reach their maximum growth and
development.
Commercial algicides for use in swimming pools are widely avail-
able. Until competent advice of the local health authority on safety
and correct dosage is determined, swimming pool chemicals should
not be used in water intended for human, livestock, or poultry
consumption.
Maintenance of a continuous and adequate chlorine residual will
effectively control the growth of algae in controlled storage facilities.
Aeration
Aeration is the process of bringing about the intimate contact be-
tween air and a liquid such as water.
Many methods are available for obtaining effective aeration, in-
cluding spraying water into the air, allowing water to fall over
a spillway in a turbulent stream, or distributing water in multiple
streams or droplets through a series of perforated plates. Although
the aeration of water may be accomplished in an open system, ade-
quate precautions should be exercised to eliminate possible external
contamination of the water. Whenever possible, a totally enclosed
system should be provided.
Aeration may be used to oxidize iron and remove odors from water,
such as those caused by hydrogen sulfide and algae. It is also effective
in increasing the oxygen content of water deficient in dissolved
oxygen. The flat taste of cistern water and distilled water may be
improved by adding oxygen. Carbon dioxide and other gases that
increase the corrosiveness of water can be eliminated largely by ef-
fective aeration, although the increase in corrosion because of increased
oxygen may partially offset the advantage of the decrease in carbon
dioxide.
Aeration of water results in partial oxidation of its dissolved ferrous
iron and thereby changes the iron into an insoluble .ferric form.
Sometimes a short period of storage permits the insoluble iron to
settle; at other times the precipitated iron cannot be removed suc-
cessfully except by filtration.
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A simple cascade device or a coke tray aerator can be incorporated
into a water supply system. In addition to aerating, the coke tray
will reduce tastes and odors.
Insects such as the chironomus fly may lay eggs in the stagnant
portion of the aerator tray. The eggs develop into small red worms,
which is the larvae stage of this insect. Proper encasement of the
aerator prevents the development of this situation. Adequate screen-
ing will provide, in addition, protection from wind-blown debris.
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Part V
Pumping, Distribution,
and Storage
PUMPING
Types of Well Pumps
Three types of pumps are commonly used in individual water dis-
tribution systems. They are the positive displacement, the centrif-
ugal, and the jet. These pumps can be used in a water system utiliz-
ing either a ground or surface source. It is desirable in areas where
electricity or other power (gasoline, diesel oil, or windmill) is avail-
able to use a power-operated pump. When a power supply is not
available, a hand pump or some other manual method of supplying
water must be used.
Special types of pumps with limited application for individual
water supply systems include air lift pumps and hydraulic rams.
Positive Displacement Pumps
The positive displacement pump forces or displaces the water
through a pumping mechanism. These pumps are of several types.
One type of positive displacement pump is the reciprocating pump.
This pump consists of a mechanical device which moves a plunger
back and forth in a closely fitted cylinder. The plunger is driven
by the power source, and the power motion is converted from a rotat-
ing action to a reciprocating motion by the combined work of a speed
reducer, crank, and a connecting rod. The cylinder, composed of a
cylinder wall, plunger, and check valve, should be located near or
below the static water level to eliminate the need for priming. The
pumping action begins when the water enters the cylinder through
a check valve. When the piston moves, the check valve closes, and in
so doing forces the water through a check valve in the plunger. With
each subsequent stroke, the water is forced toward the surface through
the discharge pipe.
Another type of positive displacement pump is the helical or spiral
rotor. The helical rotor consists of a shaft with a helical (spiral)
surface which rotates in a rubber sleeve. As the shaft turns, it pockets
or traps the water between the shaft and the sleeve and forces it to the
upper end of the sleeve.
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Other types of positive displacement pumps include the regenerative
turbine type. It incorporates a rotating wheel or impeller which has
a series of blades or fins (sometimes called buckets) on its outer edge
and a stationary enclosure called a raceway or casting. Pressures
several times that of pumps relying solely on centrifugal force can
be developed.
Centrifugal Pumps
Centrifugal pumps are pumps containing a rotating impeller
mounted on a shaft turned by the power source. The rotating im-
peller increases the velocity of the water and discharges it into a sur-
rounding casing shaped to slow down the flow of the water and convert
the velocity to pressure. This decrease of the flow further increases
the pressure.
Each impeller and matching casing is called a stage. The number
of stages necessary for a particular installation will be determined by
the amount of water required, the pressure needed for the operation
of the water system, and the height the water must be raised from the
surface of the water source.
When the pressure or amount of water required is more than can
be practicably or economically furnished by a single stage, additional
stages are used. A pump with more than one stage is called a multi-
stage pump. In a multistage pump water passes through each stage
in succession, with an increase in pressure at each stage.
Multistage pumps commonly used in individual water systems are
of the turbine and submersible types.
, Turbine Pumps. The vertical drive turbine pump consists of one
or more stages with the pumping unit located below the drawdown
level of the water source. A vertical shaft connects the pumping
assembly to a drive mechanism located above the pumping assembly.
The discharge casing, pumphousing, and inlet screen are suspended
from the pump base at the ground surface. The weight of the rotat-
ing portion of the pump is usually suspended by a thrust bearing lo-
cated in the pump head. The intermediate pump bearings may be
lubricated by either oil or water. From a sanitary point of view,
lubrication of pump bearings by water is preferable, since lubricating
oil may leak and contaminate the water.
Submersible Pumps. When a centrifugal pump is driven by a
closely coupled electric motor constructed for submerged operation as
a single unit, it is called a submersible pump. The electrical wiring to
the submersible motor must be waterproof. The electrical control
should be properly grounded to minimize the possibility of shorting
and thus damaging the entire unit. The pump and motor assembly
are supported by the discharge pipe; therefore, the pipe should be
of such size that there is no possibility of breakage.
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The turbine or submersible pump forces water directly into the
distribution system; therefore, the pump assembly must be located
below the maximum drawdown level. This type of pump can deliver
water across a wide range of pressures with the only limiting factor
being the size of the unit and the horsepower applied. When sand
is present or anticipated in the water source, special precautions should
be taken before this type of pump is used since the abrasion action of
the sand during pumping will shorten the life of the pump.
Jet (Ejector} Pumps
Jet pumps are actually combined centrifugal and ejector pumps.
A portion of the discharged water from the centrifugal pump is di-
verted through a nozzle and venturi tube. A pressure zone lower
than that of the surrounding area exists in the venturi tube; therefore,
water from the source (well) flows into this area of reduced pressure.
The velocity of the water from the nozzle pushes it through the pipe
toward the surface where the centrifugal pump can lift it by suction.
The centrifugal pump then forces it into the distribution system.
Selection of Pumping Equipment
The type of pump selected for a particular installation should be
determined on the basis of the following fundamental considerations,
1. Yield of the well or water source
2. Daily needs and instantaneous demand of the users
3. Size of pressure or storage tank
4. Size and alignment of the well casing
5. Total operating head pressure of the pump at normal delivery
rates, including lift and all friction losses
6. Difference in elevation between ground level and water level
in the well during pumping
7. Availability of power
8. Ease of maintenance and availability of replacement parts
9. First cost and economy of operation
10. Reliability of pumping equipment
The rate of water delivery required depends on the time of effective
pump operation as related to the total water consumption between
periods of pumping. Total water use can be determined from table 1,
p. 16. The period of pump operation depends upon the quantity of
water on hand to meet peak demands and the storage available. If
the well yield will permit, a pump with a minimum capacity of 600
gph should be used for the average home water system.
When the well yield is low in comparison to peak demand require-
ments, an appropriate increase in the storage capacity is required.
The life of an electric drive motor will be reduced when there is ex-
86
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Centrifugal Pump—— © © 0 © ©
Pressure
Switch
Screen
FIGURE 13. JET PUMP.
87
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Table 7.—Information on pump*
Type of pump
Reciprocating:
1. Shallow welL ,
2. Deep well .. ,.. ....
Centrifugal:
1. Shallow well
a. straight
centrifugal
(single stage)
b. Regenerative vane
turbine type (single
Impeller)
2. Deep well
a. Vertical line shaft
turbine (multi-
stage)
Practical suction
llft»
22-26 ft.
23-26 ft.
20ft. max.
28ft. max.
Impellers sab-
merged.
Usual well-
pumping depth
22-25 ft.
Up to BOO ft.
10-20 ft.
28 ft.
50-300 ft.
Usual pressure
heads
100-200 ft.
Tip to 600 ft.
above cylin-
der.
100-160 ft.
100-200 ft.
100-800 ft.
Advantages
1. Positive action.
2. T">istfiargp against vari-
able heads.
3. Pomps water containing
sand and silt.
4. Especially adapted to low
capacity and high lifts.
1. Smooth, even flow.
2. Pumps water containing
sand and silt.
3. Pressure on system Is
even and free from shock.
4. Low-starting torque.
5. Usually reliable and good
service life.
1. Same as straight centrif-
ugal except not suitable
for pumping water con-
taining sand or silt.
2. They are self-printing,
1. Same as shallow well tur-
bine.
Disadvantages
1. Pulsating discharge.
2 Subject to vibration and
noise.
3. Maintenance cost may be
high.
4. May cause destructive
pressure if operated
against closed valve.
1. Loses prime easily.
2. Efficiency depends on
operating under design
heads and speed.
1. Same as straight centrif-
ugal except maintains
priming easily
1. Efficiency depends on
operating under design
head and speed.
2. Requires straight well
large enough for turbine
bowls and housing.
3. Lubrication and align-
ment of shaft critical.
4. Abrasion from sand.
Remarks
1. Best suited for capacities
of 5—25 gpm against moder-
ate to high heads.
2. Adaptable to hand opera-
tion.
3. Can be installed in very
small diameter wells (2"
casing).
4. Pump must be set directly
over well (deep well only).
1. Very efficient pump for
capacities above 50 gpm
and heads up to about
150ft.
1. Reduction in pressure
with increased capacity
not as severe as straight
centrifugal.
-------
b. Submersible turbine
(multistage)
Jet:
1. Shallow wdL.
2. Deep veil..
Rotary:
1. Shallow well.
(Bear type)
2. Deep welL
(hellcat rotary type).
Pomp and mo-
tor sub-
merged.
lft-20 ft. below
ejector.
16-20 ft. below
ejector.
22ft.
Usually
submerged.
60-400 ft.
Up to 16-20 ft.
below ejector.
25-120 ft.
200ft. max.
22ft.
60-800 ft.
60-400 ft.
80-160 ft.
80-150 ft.
60-250 ft.
100-500 ft.
L Same as shallow well tur-
bine.
2. Easy to frost-proof Instal-
lation.
3. Short pump shaft to
motor.
1. High capacity at low
heads.
2. Simple In operation.
3. Does not have to be In-
stalled over the well.
4. No moving parts In the
well
1. Same as shallow well Jet.
1. Positive action.
2. Discharge constant under
varlble heads.
3. Efficient operation.
1. Same as shallow well
rotary.
2. Only one moving pump
device in well.
I. Bepalr to motor or pump
requires pulling from
well.
2. Sealing of electrical equip-
ment from water vapor
critical
3. Abrasion from sand.
1. Capacity reduces as lift
Increases.
2. Air In suction or return
line will stop pumping.
1. Same as shallow well Jet.
1. Subject to rapid wear if
water contains sand or
silt.
2. Wear of gears reduces
efficiency.
1. Same as shallow well
rotary except no gear
I. Difficulty with sealing has
caused uncertainty as to
service We to date.
> The amount of water re-
turned to ejector Increases
with increased lift—60%
of total water pumped at
60 ft. lift and 75% at 100
ft. lift.
1. A cutless rubber stator In-
creases life of pump.
Flexible drive coupling
has been weak point In
pump. Best adapted lor
low capacity and high
heads.
> Practical suction lift at sea level. Reduce lift 1 foot breach 1,000ft. above sea teveL
-------
cessive starting and stopping. The water system, therefore, should be
designed so that the interval between starting and stopping is as long
as is practicable but not less than 1 minute.
Pumps that deliver water to pressure tanks with limited capacity
should be capable of delivering at least 120 percent of the peak demand.
When storage for more than one day is provided, the pump should be
capable of delivering three times the maximum daily rate of water con-
sumption. Pumps delivering water to storage reservoirs with a capac-
ity of more than one week's demand should have a capacity of 150
percent of the maximum average daily rate of water consumption.
The total operating head of a pump consists of the lift (vertical dis-
tance from pumping level of the water source to the pump), the fric-
tion losses in the pipe and fittings from water source to pump, and the
discharge pressure. (See fig. 14, p. 92.)
Pumps that cannot be wholly submerged during pumping are de-
pendent on suction to raise the water from the source by reducing
the pressure in the pump column, or creating a suction. The vertical
distance from the source (pumping level) to the axis of the pump is
called the suction lift, and for practical purposes cannot exceed be-
tween 15-25 feet, depending on the design of the pump and the altitude
above sea level where it is used.
Shallow well pumps should be installed with a foot valve at the
bottom of the suction line or with a check valve in the suction line in
order to maintain pump prime.
The selection of a pump for any specific installation should be based
on competent advice (health, agriculture, geological survey depart-
ments, well-drillers, consulting engineering firms, pump manufacturers
or representatives).
A selected pump should always carry a written warranty covering
materials and mechanical performance over a specified period of time
after being placed in operation
Sanitary Protection of Pumping Facilities
The pump equipment for either power-driven or manual systems
should be so constructed and installed as to prevent the entrance of
contamination or objectionable material either into the well or into
the water that is being pumped. The following factors which should
be considered.
1. Designing the pump head or enclosure so as to prevent pollution
of the water by lubricants or other maintenance materials used
during operation of the equipment. Pollution from hand con-
tact, dust, rain, birds, flies, rodents or animals, and similar
sources should be prevented from reaching the water chamber
of the pump or the source of supply.
90
-------
2. Designing the pump base or enclosure so as to facilitate the
installation of a sanitary well seal within the well cover or
casing.
3. Installation of the pumping portion of the assembly near or
below the static water level in the well so that priming will not
be necessary.
4. Designing for frost protection, including pump drainage
within the well when necessary.
5. Overall design consideration so as to best facilitate neces-
sary maintenance and repair, including overhead clearance for
removing the drop pipe and other accessories.
When planning for sanitary protection of a pump, specific types
of installations must be considered. The following points should be
considered for the different types of installations,
Over-tTie-WeU Installation
General. The most common type of pump installation is the over-
the-well type. The pump should be placed on a raised, concrete
base rising at least 4 inches above the pumphouse floor or on an ap-
proved metal base or pumpstand furnished with the particular pump.
The top of the base should slope to allow for the drainage of any water
that may collect on it.
Power Pumps. All well casings for power-pump installations
should extend at least 6 inches above the pumproom floor or platform
slab. The base plate of a power-operated pump placed over the well
should be designed to form a watertight seal with the well cover or
casing. The base should be recessed to permit the casing or pipesleeve
to extend into it at least 1 inch above the foundation upon which the
pump base rests. The annular space between the casing and the suc-
tion and/or discharge pipe should be closed tightly with an acceptable
sanitary well seal. In installations where an open-type pump is used,
the well casing or pipesleeve should extend at least 6 inches above the
floor of the pumphouse. Powered pump equipment is the cost com-
monly used type for well installations; but, of course, when power is
not available hand-operated pumps are used.
Hand Pumps. The pump heads on most force pumps are designed
with a stuffing box surrounding the pump rod. This design provides
reasonable protection against contamination. Ordinary lift pumps
with slotted pump head tops are open to contamination and should not
be used. The pump spout should be closed and directed downward.
The pump base should be designed to serve a twofold purpose:
first, to provide a means of supporting the pump on the well cover or
casing top; and second, to protect the well opening or casing top
from the entrance of contaminated water or other harmful or objec-
64703B O—fl2 8 91
-------
Friction Head Loss
t
Pressure Head
FIGURE 14. COMPONENTS OF TOTAL OPERATING HEAD IN WELL PUMP INSTALLATIONS.
-------
tionable material. The base should be of the solid, one-piece, recessed
type, cast integrally with or threaded to the pump column or stand.
It should be of sufficient diameter and depth to permit a 6-inch well
casing to extend at least one inch above the surface upon which the
pump base is to rest. The use of a flanged sleeve imbedded in the con-
crete well cover or a flange threaded or clamped on the top of the
casing to form a support for the pump base is recommended. Suitable
gaskets should be used to insure tight closure.
The protective closing of the pump head, together with the pollu-
tion hazard incident to pump priming, makes it essential that the
pump cylinders be so installed that priming will not be necessary.
Pumphousing and Appurtenances
A pumphouse installed above the surface of the ground should be
used. (See fig. 15, p. 94.) The pumproom floor should be of water-
tight construction, preferably concrete, and should slope uniformly
away in all directions from the well casing or pipesleeve. It should
be unnecessary to use an underground discharge connection if an in-
sulated, heated pumphouse is provided. For individual installations
in rural areas, two 60-watt light bulbs, a thermostatically controlled
electric heater, or a heating cable will generally provide adequate
protection when the pumphouse is properly insulated.
In areas where power failures may occur, an emergency, gasoline-
driven power supply or pump should be considered. A natural dis-
aster, such as a severe storm, hurricane, tornado, blizzard, or flood,
may cut off power for hours or even days. A gasoline, power-driven
electrical unit could supply the power requirements of the pump,
basic lighting, refrigeration, and other emergency needs.
If the pumping rate lowers the water table in the well 10 feet or
more, the use of a well vent is recommended. The upper end of the
vent pipe, protected with proper screening, should be turned
downward.
Certain types of power pumps require that the pump system be
filled with water for priming or water-lubrication purposes before the
system is started. Water used for priming should be free of pollution.
It is desirable to provide a water-sampling tap on the discharge line
from power pumps.
Because of the pollution hazards involved, a well pit to house the
pumping equipment or to permit accessibility to the top of the well
is not recommended.
Pith** Unit*
A commercial unit known as the "pitless adapter" is available to
eliminate well pit construction. A specially designed^connection be-
tween the underground horizontal discharge pipe and the vertical
93
-------
Shingles &
Sheathing
Studs
^•Sheathing
5? Siding
— *J; \Protective—
"-Casing
W^-Casing Shoe
m- •< • , -•• ' • •'•"•->•
H
Water Bearing Sand or Gravel
-Well Screen
- Closed Bail Bottom
FIGURE 15. Pumphouse.
94
-------
casing pipe makes it possible to terminate the permanent, watertight
casing of the well at a safe height (12 inches) above the established
grade level. The underground section of the discharge pipe is per-
manently installed and it is not necessary to disturb it when repairing
the pump or cleaning the well. (See fig. 16, p. 96.)
Before considering the installation of the pitless unit, State or local
health authorities should be contacted for advice or applicable regu-
lations concernin tjie use of such a device.
DISTRIBUTION
Pipe and Fittings
For reasons of economy and ease of construction, distribution lines
for small water systems are ordinarily made up with standard
threaded, galvanized iron or steel pipe and fittings. Other types of
pipes used are cast iron, asbestos-cement, concrete, plastic, and copper.
Under certain conditions and in certain areas, it may be necessary to
use protective coatings, galvanizing, or have the pipes dipped or
wrapped. When corrosive water or soil is encountered, copper,
brass, wrought iron, plastic or cast iron pipe, although usually more
expensive initially, will have a longer, more useful life. Cast iron is
not usually available in sizes below two inches in diameter; hence, its
use is restricted to the larger transmission lines.
Plastic pipe for cold water piping is usually simple to install, has
a low initial cost, and has good hydraulic properties. When used in
a domestic water system, plastic pipe should be certified by an accept-
able testing laboratory (such as the National Sanitation Foundation)
as being nontoxic and nontaste-producing. It should be protected
against crushing and from attack by rodents. Asbestos-cement pipe
for water systems, available in the sizes required, has the advantages
of ease of installation and moderate resistance to corrosion.
Fittings are usually available in the same sizes and materials as
piping, but valves are generally cast in bronze or other alloys. In
certain soils the use of dissimilar metals in fittings and pipe may
create electrolytic corrosion problems. The use of nonconductive
plastic inserts between pipe and fittings or the installation of sacrificial
anodes is helpful in minimizing such corrosion.
Pipes should be laid as straight as possible in trenches, with air-
relief valves or hydrants located at the high points on the line.
Failure to provide for the release of .accumulated air in a pipeline
on hilly ground may greatly reduce the capacity of the line. It is
necessary that pipeline trenches be excavated deep enough to prevent
freezing in the winter. Pipes placed in trenches at a depth of more
95
-------
I nspection
Port Hole^
Pressure
Tank — -,
SUBMERSIBLE PUMP
I nspection
Port Hole
Motor-
Pressure
Tank
Suction Pipe-
Pressure Pipe
Well Casing-
Ejector-
CENTRIFUGAL-JET PUMP
INSIDE THE "PITLESS UNIT1
Inspection
Port Hole^-
Pressure
Tank
CENTRIFUGAL-JET PUMP AT
THE SIDE OF THE "PITLESS UNI?1
FIGURE 16. PITLESS UNITS.
-------
than three feet will help to keep the water in the pipeline cool during
the summer months.
Pipe Capacity and Head Lett
The pipeline selected should be adequate to deliver the required
peak flow of water without excessive loss of head, i.e., without de-
creasing the discharge pressure below a desirable minimum. The
normal operating water pressure for household or domestic use ranges
from 15 to 60 pounds per square inch,1 or about 35 to 140 feet of
head at the fixture.
The capacity of a pipeline is determined by its size, length, and
interior surface condition. Assuming that the length of the pipe is
fixed and its interior condition established by the type of material,
the usual problem in design of a pipeline is that of determining the
required diameter.
The correct pipe size can be selected with the aid of fig. 17, p. 198,
which gives size as a function of head loss, H, length of pipeline, L,
and peak discharge, Q. As an example of the use of fig. 17, p. 98,
suppose that a home and farm installation is served by a reservoir
a minimum distance of 500 feet from the point of use, one whose
surface elevation is at least 150 feet above the level of domestic
service, and in which a minimum service pressure of 30 pounds per
square inch is required. It will be necessary first to determine the
maximum operating head loss, i.e., the difference in total head and
the required pressure head at the service.
H= 150-2.3X30=150-69=81 feet
The maximum peak demand which must be delivered by the pipeline
is determined to be 30 gallons per minute.
Q=30 gallons per minute
The hydraulic gradient is 0.162 feet per foot.
FT R1
T~ — Rnn— 0.162 feet per foot
Entering fig. 17, p. 98, with the computed values of H/L and Q,
one finds that the required standard galvanized pipe size is approxi-
mately 1% inches. Since pipes are available only in standard dimen-
sions, standard pipe of \% inches in diameter, (the next size) should
be used.
Additional head losses may be expected from the inclusion of
fittings in the pipeline. These losses may be expressed in terms of
the equivalent to the length and size of pipe which would produce
1 One pound per square inch is the pressure produced by a column of water
2.31 feet high.
97
-------
0.1
0.09
0.08
0.07
0.06
0.01
0.009
0.008
0.007
0.006
0.001
0.0009
0.0008
0.0007
0.0006
(Hazen - William Formula C • 100)
1W 11/2" 2" 2 ]S2
Nominal Diameter - Standard Galvanized Pipe
98
-------
an equivalent loss if, instead of adding fittings, we added additional
pipe. Table 8 lists some common fitting losses in terms of an equiva-
lent pipe length.
TdbU 8.—Allowance In equivalent length of pipe tor friction loss In valves and
threaded fittings
Diameter
of fitting
Inehet
%
%
%
1
Ui
1/2
2
2^
3
3H
4
5
6
90° std.
ell
Feet
1
2
2.5
3
4
5
7
8
10
12
14
17
20
45° std.
ell
Feet
0.6
1,2
1.5
1.8
2.4
3
4
5
6
7
8
10
12
90° side
tee
Feet
1.5
3
4
5
6
7
10
12
15
18
21
25
30
Coupling
or straight
run
Feet
0.3
0. 6
0.8
0.9
1.2
1.5
2
2.5
3
3. 6
4
5
6
Gate
valve
Feet
0.2
0.4
0.5
0.6
0.8
1.0
1.3
1.6
2
2.4
2.7
3.3
4
Globe
valve
Feet
8
15
20
25
35
45
55
65
80
100
125
140
165
Angle
valve
Feet
4
8
12
15
18
22
28
34
40
50
55
70
80
In the example given above the inclusion of two gate valves (open),
two standard elbows, and two standard tees (through) would produce
a head loss equivalent to 15 feet of 1%-inch pipe. From fig. 17,
p. 98 one finds that by using 515 feet of 1%-inch pipe instead of
the actual length of 500 feet (H/L=0.157), the capacity of the system
for the same total head loss is about 38 gallons per minute, a satisfac-
tory discharge.
It can be seen from this example that fitting losses are not particu-
larly important for fairly long pipelines, say greater than about 300
feet. For pipelines less than 300 feet, fitting losses are very important
and have a direct bearing on pipe selected; therefore, they should be
calculated carefully.
Globe valves which do produce large head losses should be avoided
in main transmission lines for small water systems.
Interior piping, fittings, and accessories should conform to the mini-
mum requirements for plumbing of the National Plumbing Code2 or
equivalent applicable plumbing code of the locality.
* Obtainable at the American Society of Mechanical Engineers, 29 West 39th
Street, New York 18, New York.
99
-------
Protection of Distribution Systems
The sanitary protection of new or repaired pipelines can be facili-
tated by proper attention to certain details of construction. All con-
nections should be made under dry conditions, either in a dry trench
or, if it is not possible to completely dewater the trench, above the
ground surface. Soiled piping should be thoroughly cleaned and
disinfected before connections are made. Flush valves or clean-outs
should be provided at low points where there is no possibility of
flooding.
When not properly designed or installed, frostproof hydrants may
permit contamination to enter the water system. Such hydrants
should be provided with suitable drainage to a free atmosphere out-
let where possible. The drainage from the base of the hydrant should
not be connected to a seepage pit which is subject to pollution or to
a sewer. The water supply inlet to water tanks used for stock, laundry
tubs, and other similar installations should be placed with an air gap
(twice pipe diameter) above the flooding level of the fixtures to
prevent danger of back siphonage. There should be no cross-con-
nection, auxiliary intake, bypass, or other piping arrangement whereby
polluted water or water of questionable quality can be discharged
or drawn into the domestic water supply system.
Before a distribution system is placed in service it should be com-
pletely flushed and disinfected.
Disinfection of Water-Distribution System
General
These instructions cover the disinfection of water distribution sys-
tems and attendant standpipes or tanks. It is always necessary to dis-
infect a water system before placing it in use under the following
conditions:
1. Disinfection of a system which has been in service with raw
or polluted water, preparatory to transferring the service to
treated water.
2. Disinfection of a new system upon completion and preparatory
to placing in operation with treated water or water of satis-
factory quality.
3. Disinfection of a system after completion of maintenance and
repair operations.
Procedure
The entire system, including tank or standpipe, should be thoroughly
flushed with water to remove any sediment which may have collected
100
-------
during operation with raw water. Following flushing, the system
should be filled with a disinfecting solution of calcium hypochlorite
and treated water. This solution is prepared by adding 1.2 pounds
of high-test 70% calcium hypochlorite to each 1,000 gallons of water.
A mixture of this kind provides a solution having not less than 100
mg/1 of available chlorine.
The disinfectant should be retained in the system, tank, or stand-
pipe, if included, for not less than 24 hours, then examined for resi-
dual chlorine and drained out. If no residual chlorine is found
present, the process should be repeated. The system is next flushed
with treated water and put into operation.
STORAGE
Determination of Storage Volume
Three types of storage facilities are commonly employed for in-
dividual water supply systems. They are pressure tanks, elevated
storage tanks, and ground-level reservoirs and cisterns.
When ground-water sources are used for a water supply, the water-
bearing formation tapped by one or more wells constitutes a natural
storage area. The result is that only small artificial storage facilities
may be needed.
Pressure Tanks. Pressure in a distribution system served by a
pneumatic tank is maintained by pumping water directly to the tank
from the source. This pumping action compresses a volume of en-
trapped air. The air pressure equal to the water pressure in the tank
can be controlled between desired limits by means of pressure switches
which stop the pump at the maximum setting and start it at the mini-
mum setting. The capacity of pressure tanks is usually small when
compared to the total daily water consumption. Tanks are customarily
designed to accommodate only momentary peak demands because only
10 to 20 percent of tank capacity is available. The maximum steady
demand which can be delivered by a pneumatic system is equal to the
pump capacity.
Generally, the pressure tank should be approximately 10 times the
pump capacity in gallons per minute. When the well yield permits,
it is advisable to select a pump large enough to satisfy the peak
demand periods.
Pressure tanks for individual home installations should have a ca-
pacity of at least 42 gallons or about 10 or 15 gallons per person
served.
101
-------
The following equation is suggested for use in estimating the size
of a pressure storage tank needed in larger water supply systems.
The volume can be computed with the aid of the formula below.3
Q=i%
Where Q is the tank volume in gallons, QTO is equal to 15 minutes of
storage at peak rate, PI is the minimum absolute operating pressure
(gauge pressure plus atmospheric pressure or 14.7 pounds per square
inch), and P2 is the maximum absolute pressure. As an example of
the use of the equation, suppose that a pressure tank was to be used
for a larger water system which has a peak demand of 30 gallons per
minute and that the gauge pressure on the tank could be allowed to
vary from 40 to 60 pounds per square inch. Then
Pi 40+14.7 n»n
and Qm= 15 X 30=450 gallons 3
A tank which holds 1667 gallons is required.
=1667 gallons
When a pressure tank is provided in the distribution system there
is no difficulty with water hammer. Sometimes it may be necessary
to provide an air chamber on the discharge line from the well located
near the pump to minimize the effects caused by water hammer.
Elevated Storage. Elevated tanks should have a capacity which
is at least equal to two days' average consumption requirement.
Larger storage volume may be necessary to meet special demands
such as firefighting or equipment cleanup operations.
Ground-Level Reservoirs and Cisterns. Reservoirs which receive
surface runoff should generally be large enough to supply the average
daily demand over a drought period of maximum length. Cisterns
are customarily designed with sufficient capacity to provide water
during periods less than one year in duration.
Protection of Storage Facilities
Suitable storage facilities for relatively small systems may be con-
structed of concrete, steel, brick, and sometimes of wood above the land
surface, or of concrete or brick if partially or wholly below the ground
surface. Such storage installations should receive the same
3J. A. Salvato, Jr., Environmental Sanitation (New York, John "Wiley and
Sons, 1958).
102
-------
Screened Overflow
and Vent
-Valve and
Box
-^
air1
il
i
i
II
-Screened Intel
I '1 and Outlet
11 rManholeand
Cover /'
/
-Screened
Drain
-Switch
Control
PLAN
Lock
•
Switch ControU „
-Manhole Cover *»T
Screened Overflow
and Vent
/—Screened Inlet
/ and Outlet
Screened Drain
Floor to Drain
ELEVATION
18. Typical Concrete Reservoir.
T03
-------
Overlapping, Circular Iron Cover
Iron Cover
Galvanized Sheet Metal
Over Wooden Cover
Concrete Cover
MANHOLE COVERS
Telescoping Joint
Foot Piece or Brick
TYPICAL VALVE AND BOX
No. 16 Mesh
Copper Screen
—Reservoir or
Cistern Wall
Coupling
I
y
*. LJ:V'
&li
2
Pipe Connection With
Anchor Flange Casting
Top of Cistern
or Reservoir
OVERFLOW AND VENT
VENT
FIGURE 19. TYPICAL VALVE AND BOX, MANHOLE COVERS, AND PIPING INSTALLATIONS.
104
-------
care as cistern installations in the selection of a suitable location and
provision against contamination. Asphalt or tar for waterproofing
the interior of storage units is not recommended because of the objec-
tionable taste imparted to the water and the possibility of undesirable
chemical reaction with the materials used for treatment. Specifi-
cations covering the painting of water tanks are available from the
American Water Works Association. Appropriate Federal, State, or
local health agencies should be consulted relative to approved paint
coatings for interior tank use.
All storage tanks for domestic water supply should be completely
covered and so constructed as to prevent the possibility of pollution
of the tank contents by outside water or other foreign matter. Fig.
18, p. 103, and fig. 19, p. 104, show some details for manhole covers
and piping connections to prevent the entrance of pollution from sur-
face drainage. Concrete and brick tanks should be made watertight
by a lining of rich cement mortar. Wood tanks are generally con-
structed of redwood or cypress and while filled they will remain water-
tight. All tanks require adequate screening of any openings to
protect against the entrance of small animals, mosquitoes, flies, and
other small insects.
Tanks containing water to be used for livestock should be partially
covered and so constructed that cattle will not enter the tank. The
area around the tank should be sloped to drain away from the tank.
Fig. 18, p. 103, shows a typical concrete reservoir with screened
inlet and outlet pipes. This figure also illustrates the sanitary man-
hole cover. The cover should overlap by at least 2 inches a rim ele-
vated at least 4 inches to prevent drainage from entering the reservoir.
This type of manhole frame and cover should be designed so that it
may be locked to prevent access by unauthorized persons.
The water in storage tanks, cisterns, or pipelines should not be pol-
luted with an emergency water supply that has been polluted at its
source or in transit.
Disinfection of storage facilities subsequent to construction or repair
should be carried out in accordance with the recommendations stated
under "Disinfection of Water Distribution System" in this part of
the manual.
105
-------
Bibliography
Partial List of References on Individual Water
Supply Systems
American Public Health Association, American Water Works Association and
Water Pollution Control Federation, Standard Methods for the Examination
of Water and Wastewater, llth ed. New York, American Public Health
Association, Inc., 1960.
American Water Works Association, Water Quality and Treatment, 2nd ed. New
York, American Water Works Association, Inc., 1950.
Bauman, E. Robert, "Should Small Water Supplies Be Superchlorinated?"
Parts 1 and 2. Water and Sewage Works, Vol. 108 (December 1961) pp. 463-
465; Vol. 109 (January 1962) pp. 21-23.
Bowman, Isaiah, Well-Drilling Methods, U. S. Geological Survey, Water Supply
Paper 489, 1923,
Butterfleld, C. J., "Bactericidal Properties of Chloromines and Free Chlorine in
Water." Public Health Reports, (1948).
Caldwell, Elfreda L., and Parr, Leland W., "Ground Water Pollution and the
Bored Hole Latrine." Journal of Infectious Diseases, Vol. 61 (1937), pp.
148-183.
Caldwell, Elfreda L., "Pollution Flow from Pit Latrines When an Impervious
Stratum Closely Underlies the Flow." Journal of Infectious Diseases, Vol.
61 (1937), pp. 270-288.
Caldwell, Elfreda L., "Pollution Flow from a Pit Latrine When Permeable Soils
of Considerable Depth Exist below the Pit." Journal of Infectious Diseases,
Vol. 62 (1938), pp. 225-258.
Caldwell, Elfreda L., "Studies of Subsoil Pollution in Relation to Possible Con-
tamination of the Ground Water from Human Excreta Deposited in Experi-
mental Latrines," Journal of Infectious Diseases, Vol. 62 (1938), pp. 272-292.
California Water Pollution Control Board, Investigations of Travel Pollution.
Publication No. 11, 1954.
Fiedler, A.G., "The Construction and Protection of Drilled Wells." Journal of
American Water Works Association, Vol. 5. (1933), pp. 72-82.
Fiedler, A. G., "Proper Methods of Well Construction." Howell Drillers News,
Vol. 10 (April and May, 1931), Water Works Engineering, Vol. 84 (1931),
pp. 444-446.
Fiedler, A. G., "The Occurrence of Ground Water with Reference to Contami-
nation." Journal of American Water Works Association, Vol. 28 (1936),
pp. 1954-1962.
Garver, Harry L., Safe Water for the Farm. U.S. Department of Agriculture,
Farmers Bulletin 1978, 1948.
Goldstein, Melvin, McCabe, L. J., Jr., and Woodward, Richard L., "Continuous-
Flow Water Pasteurizer for Small Supplies." Journal of American Water
Works Association (February 1960).
Hodgkinson, Carl, Removal of Coliform Bacteria from Sewage by Percolation
through Soil. University of California, Sanitary Engineering Research
Laboratory, IER Series 90, No. 1,1955.
Lord, Thomas H., Lipper, Ralph I., and Stover, Harold E., Purifying Pond Water.
Kansas State College, Engineering Extension Department, December 1957.
Meinzer, O. E., and Others, Hydrology; Physics of the Earth. New York, Mc-
Graw-Hill Book Company, Inc., 1942, Vol. 9.
Meinzer, O. E., Occurrence of Ground Water in the United States. U.S. Geologi-
cal Survey, Water Supply Paper 489,1923.
National Association of Domestic and Farm Pump Manufacturers, Manual of
Water Supply and Equipment, 1953.
National Fire Protection Association, "Water Systems for Fire Protection on
Farms, National Fire Codes, Vol. IV (Boston, 1946).
106
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National Lime Association, Water Supply and Treatment, 8th ed. National
Lime Association Bulletin 211,1957.
Nordell, Eskell, Zeolites-Mining, Processing, Manufacture and Use, Michigan
Engineering Experimental Station Bulletin 61,1935.
Orlob, G, T., and Krone, R. B., Movement of Coliform Bacteria through Porous
Media. University of California, Sanitary Engineering Research Labora-
tory, Report to Sponsor, U.S.P.H.S. Grant No. 4286,1956.
Salvato, J. A., Jr., "Design of Small Water Systems." Public Works (May 1960).
Salvato, J. A., Jr., Environmental Sanitation, 1st ed. New York, John Wiley &
Sons, Inc., 1958.
"Sanitation Manual for Public Ground Water Supplies." Public Health Reports,
Vol. 59 (1944), pp. 137-177.
Stiles, C. W., Crohurst, H. R., and Thomson, G. E., Experimental Bacteria and
Chemical Pollution of Wells Via Ground Water and the Factors Involved.
U.S. Hygienic Laboratory Bulletin 147,1927.
Tennessee Valley Authority, Pumps and Plumbing for the Farmstead, November
1940.
Thomas, J. B., Sanitary Methods for Rural Water Supplies and Systems. U.S.
Department of Agriculture, Soil Conservation Service, 1940.
U.S. Department of Agriculture, Water, The Yearbook of Agriculture. House
Document No. 32, Government Printing Office, Washington, 1955.
U.S. Department of Agriculture, Water Development and Sanitation Handbook.
Forest Service Publication No. FSH 5652.1 (1962).
U.S. Department of the Army, Field Water Supply Technical Manual No. 5-700,
Government Printing Office, Washington, 1961.
U.S. Department of the Army, Wells. Technical Manual No. 5-297, Government
Printing Office, Washington, 1957.
U.S. Department of Health, Education, and Welfare, Manual of Recommended
Water-Sanitation Practice. Public Health Service Publication No. 525,
Government Printing Office, Washington, 1946.
U.S. Department of Health, Education, and Welfare, "1962 Public Health Service
Drinking Water Standards." Public Health Service Publication No. 956.
(1962.)
Wagner, E. G., and Lanoix, J. N., Water Supply for Rural Areas and Small
Communities. World Health Organization Monograph Series No. 42, Geneva,
1959.
Water Systems Council. Water System and Treatment Handbook, 3rd ed.
Wisconsin State Board of Health, Sanitary Engineering Bureau. Methods of
Cement Grouting for Sanitary Protection of Wells, 1938.
AVisconsin State Board of Health, Wisconsin Well Construction Code, 1939.
Wright, F. B., Rural Water Supply and Sanitation, 2nd ed. New York, John
Wiley and Sons, 1956.
647035 O—«S 9 107
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Appendix A
Recommended Procedure for Cement Grouting of
Wells for Sanitary Protection1
The annular open space on the outside of the well casing is one of
the principal avenues through which undesirable water and contamina-
tion may gain access to a well. The most satisfactory way of elim-
inating this hazard is to fill the annular space with neat cement grout.
To accomplish this satisfactorily, careful attention should be given
to see that:
1. The grout mixture is properly prepared.
2. The grout material is placed in one continuous mass.
3. The grout material is placed upward from the bottom of the
space to be grouted.
Neat cement grout should be a mixture of cement and water in the
proportion of 1 bag of cement (94 pounds) and 5 to 5i/fc gallons of
clean water. Whenever possible, the water content should be kept
near the lower limit given. Hydrated lime to the extent of 10 per-
cent of the volume of cement may be added to make the grout mix
more fluid and thereby facilitate placement by the pumping equip-
ment. Mixing of cement or cement and hydrated lime with the water
must be thorough.
GROUTING PROCEDURE
The grout mixture must be placed in one continuous mass; hence,
before starting the operation, sufficient materials should be on hand
and other facilities available to accomplish its placement without
interruption.
Restricted passages will result in clogging and failure to complete
the grouting operation. The minimum clearance at any point, in-
cluding couplings, should not be less than li/£ inches. When grouting
through the annular space, the grout pipe should not be less than 1
inch nominal diameter. As the grout moves upward, it picks up much
loose material such as results from caving. Accordingly, it is desir-
able to waste a suitable quantity of the grout which first emerges from
the drill hole.
In grouting a well so that the material will move upward, there
are two general procedures that may be followed. The grout pipe
may be installed within the well casing or in the annular space be-
tween the casing and drill hole if there is sufficient clearance to permit
this. In the latter case, the grout pipe is installed in the annular
1 This information has been taken principally from a pamphlet of the Wisconsin
State Board of Health entitled "Method of Cement Grouting for Sanitary Protec-
tion of Wells." The subject is discussed in greater detail in that publication.
(Note: Publication is out of print.)
108
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space to within a few inches of the bottom. The grout is pumped
through this pipe, discharging into the annular space, and moving
upward around the casing, finally overflowing at the land surface,
In 3 to 7 days the grout will be set, and the well can be completed
and pumping started.
When the grout pipe is installed within the well casing, the casing
should be supported a few inches above the bottom during grouting
to permit grout to flow into the annular space. The well casing
is fitted at the bottom with an adapter threaded to receive the grout
pipe and a check valve to prevent return of grout inside of the casing.
After grout appears at the surface, the casing is lowered to the bot-
tom and the grout pipe is unscrewed immediately and raised a few
inches. A suitable quantity of water should then be pumped through
it, thereby flushing any remaining grout from it and the casing. The
grout pipe is then removed from the well and 3 to 7 days are allowed
For setting of the grout. The well is then cleared by drilling out the
adapter, check valve, plug, and grout remaining within the well.
A modification of this procedure is the use of the well casing itself
to convey the grout to the annular space. The casing is suspended in
the drill hole and held several feet off the bottom. A spacer is in-
se'rted in the casing. The casing is then capped and connection made
from it to grout pump. The estimated quantity of grout, including
a suitable allowance for filling of crevices and other voids, is then
pumped into the casing. The spacer moves before the grout, in turn
forcing the water in the well ahead of it. Arriving at the lower
casing terminal, the spacer is forced to the bottom of the drill hole,
leaving sufficient clearance to permit flow of grout into the annular
space and upward through it.
After the desired amount of grout has been pumped into the casing,
the cap is removed and a second spacer is inserted in the casing. The
cap is then replaced and a measured volume of water sufficient to fill
all but a few feet of the casing is pumped into it. Thus all but a
small quantity of the grout is forced from the casing into the annular
space. From 3 to 7 days are allowed for setting of the grout. The
spacers and grout remaining in the casing and drill hole are then
drilled out and the well completed.
If the annular space is to be grouted for only part of the total depth
of the well, the grouting can be carried out as directed above when the
well reaches the desireoaepth, and the well can then be drilled deeper
by lowering the tools inside of the first casing. In this type of con-
struction, where casings of various sizes telescope within each other,
a seal should be placed at the level where the telescoping begins, that
is, in the annular space between the two casings. The annular space
for grouting between two casings should provide a clearance of at least
U/2 inches, and the depth of the seal should be not less than 10 feet.
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Appendix B
Bacteriological Quality
SAMPLING
In the event that bacteriological samples must be obtained without
technical assistance, it is possible to insure satisfactory results by
carefully following these steps:
1. Use a sterile sample bottle provided by the laboratory that
will examine the sample.
2. Be very careful so that NOTHING except the water to be
analyzed will come in contact with the inside of the bottle or
the cap.
3. Inspect the outside of the faucet. If the faucet leaks around
the handle, a different sampling point should be selected.
4. Clean and dry the outside of the faucet.
5, Allow the water to run for at least one-half minute before the
sample of water is collected.
6. When filling the bottle, be sure that the bottle is held so that
no water which contacts the hands runs into the bottle.
7. Deliver the sample immediately to the laboratory. If the delay
between collection and examination exceeds 24 hours the re-
sults may not be accurate.
EXAMINATIONS
At the present time there are two methods used for determining the
bacteriological quality of a water supply: the multiple-tube fermenta-
tion technique and the membrane filter technique.
The multiple-tube fermentation technique for determining the pres-
ence of coliform bacteria requires two to four days to obtain results
after the sample is received in the laboratory. It also requires the
use of trained personnel and centralized laboratory facilities.
In recent years the membrane filter technique "has been accepted as
a standard method for making a quick and relatively simple coliform
determination. This technique permits the examination of a greater
number of samples than the multiple-tube test, with increased sensi-
tivity in coliform detection. The most important benefit derived from
the use of this technique is that definite results are obtained in 18 to 20
hours, a much shorter time than with the multiple-tube procedure.
The membrane filter method also permits field testing with self-con-
tained portable kits which are commercially available. The membrane
filter technique may be used in disasters and in emergencies such as
those arising from floods or hurricanes, where the time which elapses
before results of the examination are available is an important con-
sideration in the prompt initiation of protective measures.
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Appendix C
Emergency Disinfection
When ground water is not available and surface water must be used,
avoid sources containing floating material or water with a dark color
or an odor. The water taken from a surface source should be taken
from a point upstream from any inhabited area and dipped, if pos-
sible, from below the surface.
When the home water supply system is interrupted by natural or
other forms of disaster, limited amounts of water may be obtained by
draining the hot water tank or melting ice cubes.
In case of a nuclear attack, surface water should not be used for
domestic purposes unless it is first found to be free from excessive
radioactive fallout. The usual emergency treatment procedures do
not remove such substances. Competent radiological monitoring serv-
ices as may be available in local areas should be relied upon for this
information.
There are two general methods by which small quantities of water
can be effectively disinfected. One method is by boiling. It is the
most positive method by which water can be made bacterially safe
to drink. Another method is chemical treatment. If applied with
care, certain chemicals will make most waters free of harmful or
pathogenic organisms.
When emergency disinfection is necessary, the physical condition
of the water must be considered. The degree of disinfection will be
reduced in water that is turbid. Turbid or colored water should be
filtered through clean cloths or allowed to settle, and the clean water
drawn off before disinfection. Water prepared for disinfection
should be stored only in clean, tightly covered, noncorrodible
containers.
METHODS OF EMERGENCY DISINFECTION
1. Boiling. Vigorous boiling for ONE full minute will kill any
disease-causing bacteria present in water. The flat taste of boiled
water can be improved by pouring it back and forth from one con-
tainer into another, by allowing it to stand for a few hours, or by
adding a small pinch of salt for each quart of water boiled.
2. Chemical Treatment. When boiling is not practical, chemical
disinfection should be used. The two chemicals commonly used are
chlorine and iodine.
a. Chlorine
(1) Chlorine Bleach. Common household bleach contains a
chlorine compound which will disinfect water. The procedure to be
followed is usually written on the label. When the necessary pro-
cedure is not given, one should find the percentage of available
chlorine on the label and use the information in the following tabula-
tion as a guide.
Ill
-------
Available chlorine
1%
4-6%
7-10%
'o
Drops per
quart of
clear water *
10
2
1
1 If strength is unknown add 10 drops
per quart to purify.
s Double amount for turbid or colored
water.
The treated water should be mixed thoroughly and allowed to
stand for 30 minutes. The water should have a slight chlorine odor;
if not, repeat the dosage and allow the water to stand for an addi-
tional 15 minutes. If the treated water has too strong a chlorine
taste, it can be made more palatable by allowing the water to stand
exposed to the air for a few hours or by pouring it from one clean
container to another several times.
(2) Granular Calcium HypocMorite. Add and dissolve one
heaping teaspoon of high-test granular calcium hyppchlorite
(approximately 1/4 ounce) for each two gallons of water. This mix-
ture will produce a stock chlorine solution of approximately 500
mg/1, since the calcium hypochlorite has an available chlorine ^equal
to 70% of its weight. To disinfect water, add the chlorine solution in
the ratio of one part of chlorine solution to each 100 parts of water
to be treated. This is roughly equal to adding 1 pint (16 oz.) of stock
chlorine solution to each 12.5 gallons of water to be disinfected. ^ To
remove any objectionable chlorine odor, aerate the water as described
above.
(3) Chlorine Tablets. Chlorine tablets containing the neces-
sary dosage for drinking water disinfection can be purchased in a
commercially prepared form. These tablets are available from drug
and sporting goods stores and should be used as stated in the instruc-
tions. When instructions are not available, use one tablet for each
quart of water to be purified.
b. Iodine
(1) Tincture of Iodine, Common household iodine from the
medicine chest or first aid package may be used to disinfect water.
Add 5 drops of 2% United States Pharmaceutical (U.S.P.) tincture
of iodine to each quart of clear water. For turbid water add 10 drops
and let the solution stand for at least 30 minutes.
(2) Iodine Tablets, Commercially prepared iodine tablets
containing the necessary dosage for drinking water disinfection can be
purchased at drug and sporting goods stores. They should be used
as stated in the instructions. When instructions are not available, use
one tablet for each quart of water to be purified.
Water to be used for drinking, cooking, making any prepared
drink, or brushing the teeth should oe properly disinfected.
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Appendix D
Suggested Ordinance1
The following is suggested for consideration in drafting an ordi-
nance for local application, subject to the approval of the appropriate
legal authority, to permit the exercise of appropriate legal controls
over non-public ground-water supply systems used for domestic pur-
poses, to assure that the quality of such water is protected by the
proper construction and installation of wells, pumping equipment and
appurtenant pipe lines.
Persons utilizing this draft as a guide are urged to familiarize
themselves with applicable legal requirements governing the adoption
of ordinances of this kind and to adapt the suggested language as may
be necessary to meet such requirements.
AN ORDINANCE GOVERNING NON-PUBLIC GROUND-WATER SUPPLY
SYSTEMS
An ordinance regulating the development of ground-water systems
and the location, development, construction, or reconstruction of wells;
authorizing the establishment of standards for the location, construc-
tion, or reconstruction, installation or operation of wells, appurtenant
pumping equipment and ground-water supply systems; providing for
the issuance of permits for the construction, or reconstruction of wells,
and ground-water supply systems, and for the installation of pumping
equipment for wells; providing for the licensing of persons engaged in
the business of well-drilling or installation of well pumps; prescribing
duties, responsibilities, and authorities of the health department;
and providing for the enforcement of this ordinance and penalties
for the violation of its provisions.
Be it ordained by the of the
municipality of1 as follows:
Section I—Scope
1.1 This ordinance applies to all wells intended or used for supplying
ground water for domestic purposes except that it shall not apply to
those wells which are licensed or subject to approval by a State agency
as public or community water supplies.
Section //—Definitions
2.1 For the purpose of this ordinance the following terms shall have
the meaning ascribed to them in this section:
lThi8 information has been taken principally from a "Guide Enabling Act
& Sanitary Code for Non-Public Water Well Installations," issued by the Sub-
committee on Wells & Equipment, Water Supply Committee, Conference of State
Sanitary Engineers. May 1960.
1 Insert proper legal jurisdiction.
113
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2.1.1 Health officer means the legally designated health authority
of the (name of political subdivision) or his authorized
representative.
2.1.2 Ground water means water which is present, flowing, or
located below the surface of the earth.
2.1.3 Well shall mean an excavation or opening into the ground
made by digging, boring, drilling, driving, or other
methods.
2.1.4 Ground-water supply system means a well, and all appurte-
nances thereto for the delivery of ground water for use,
including pumps and piping.
2.1.5 Domestic purposes include use for human consumption and
for the processing and preparation of food for human
consumption.
2.1.6 Permit shall mean a written permit issued by the health
officer permitting the construction of a ground-water sup-
ply system.
2.1.7 Person shall mean and include any individual, firm, public
or private corporation, association, partnership, or other
entity.
Section III—Establishment of Standards for Ground-Water Supply Sys-
tems by the Health Officer
3.1 The health officer, in order to protect the health and safety of the
people of (name of political subdivision) and of the general public
is authorized and directed, after public hearing to adopt, promulgate,
and amend, from time to time, rules and regulations governing the lo-
cation, design, construction, reconstruction, installation, operation,
and maintenance of ground-water supply systems. Such rules and
regulations shall establish such minimum standards as, in the judg-
ment of the health officer, are necessary to insure that ground-water
supply systems are protected against contamination and pollution and
will not constitute a health hazard.
3.2 The health officer shall file a certified copy of all rules and regu-
lations which he may adopt with the clerk of (name of political sub-
division).
3.3 Rules and regulations adopted by the health officer shall have the
same force and effect as the provisions of this ordinance and the
penalty for violation thereof shall be the same as the penalty for
violation of the provisions of this ordinance as herein provided.
3.4 Notice of public hearings for the consideration, adoption, and
amendment of rules and regulations authorized herein shall specify
the date, time, and place of such hearings. Such notice shall be pub-
lished at least times in a newspaper of general circulation in
(name of political subdivision) and in such other publications as the
health officer may determine at least days before such public
hearing.
Section IV—Permits
4.1 It shall be unlawful for any person to construct, alter, or extend
a ground-\vater supply system within the (name of political subdivi-
114
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sion) unless he holds a valid permit issued by the health officer in the
name of the applicant for the specific construction, alteration, or ex-
tension proposed.
4.2 All applications for permits shall be made to the health officer,
who shall issue a permit in the applicant's name upon compliance by
applicant with provisions of this ordinance and any regulations
adopted hereunder.
4.3 The health officer may (shall)3 refuse to grant a permit for the
construction of an individual ground-water supply system where
adequate public or community water system distribution lines are
located within feet of the premises to be served by the proposed
ground-water supply system.
4.4 Applications for permits shall be in writing, shall be signed by
the applicant, and shall include the following:
4.4.1 Name and address of the applicant.
4.4.2 Lot and block number of property determined by the Office
of the Tax Assessor, or the equivalent unit of the (local
government) on which construction, alteration, or extension
is proposed.
4.4.3 Complete plan of the proposed water facility, with sub-
stantiating data, if necessary, attesting to its compliance
with the minimum standards of the health officer.
4.4.4 Location of the nearest distribution line of a public or
community water supply system.
4.4.5 Such further information as may be required by the health
officer to substantiate that the proposed construction, alter-
ation, or extension complies with regulations promulgated
by the health officer.
4.5 A complete plan for the purpose of obtaining a permit to be
issued by the health officer shall include:
4.5.1 The number, location, and size of all ground-water supply
systems to be constructed, altered, or extended.
4.5.2 The location of water supplies, water-supply piping, exist-
ing sewage-disposal facilities, buildings or dwellings, or
other potential sources of ground-water pollution, and ad-
jacent lot lines.
4.5.3 Plans of the proposed water-supply facilities to be con-
structed, altered, or extended.
4.6 Any person whose application for a permit under this ordinance
has been denied may within 10 days after official notification of such
action file a written request for a hearing before the health officer.
Such hearing shall be held within 30 days after the receipt of the
request by the health officer and upon reasonable notice to the appli-
cant. The health office shall affirm, modify, or revoke the denial or
issue the permit on the basis of the evidence presented at the hearing.
* Alternative provisions.
115
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6.2 The health officer is authorized to adopt, promulgate, and a
from time to time rules and regulations establishing qualificatioi
Section V—Inspections
5.1 The health officer is hereby authorized and directed to make such
inspections before, during, and after construction of ground-water
supply systems as may be deemed necessary to determine satisfactory
compliance with this ordinance and regulations promulgated here-
under.
5.2 It shall be the duty of the owner or occupant of a property to
give the health officer free access to the property at reasonable times
for the purpose of making such inspections as are, necessary to de-
termine compliance with the requirements of this ordinance and reg-
ulations promulgated hereunder.
Section VI—licensing of Well-Drillers and Pump Installers*
6.1 It shall be unlawful for any person to engage in the business of
well-drilling or of installing pumps for wells within the police juris-
diction of (name of political subdivision) unless he holds a valid
license issued to him by the health officer.
amend
tions for
well-drillers and pump installers after a public hearing as provided in
section 3.4 of this ordinance.
6.3 An application for a license to engage in the business of well
drilling or pump installing shall be made in writing in a form pre-
scribed by the health officer, (shall be accompanied by the deposit of
a fee of dollars), and shall include such information as the health
officer deems necessary to determine the qualifications of the applicant.
6.4 Each license issued hereunder shall be valid for a period of —
years and shall be renewable for succeeding year periods upon
payment of a renewal fee of dollars.
6.5 Any person whose application for a license under this section has
been denied may request and shall be granted a hearing before the
health officer in accordance with the hearing procedure set out in sec-
tion 4.6 of this ordinance.
6.6 Whenever the health officer finds that a licensee under this section
is, or has engaged in practices which are in violation of any provision
of this ordinance or any rule or regulation adopted pursuant thereto,
the health officer may give notice in writing to the licensee describing
the alleged violation and stating that an opportunity for hearing will
be provided to the licensee to show cause why his license should not
be suspended or revoked. If a written request for such hearing is
filed with the health office within 10 days of receipt of the notice,
such hearing shall be in accordance with the procedure provided by
section 4.6.
6.7 At the conclusion of the hearing, or if no hearing is requested,
the hearing officer may dismiss the notice, suspend the license for a
period of not more than one year, and in cases of willful or serious
* Optional provision.
116
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violation of this ordinance or of rules and regulations adopted here-
under, revoke the license. Such suspension or revocation shall be in
addition to the penalties provided for nerein.
6.8 No application for a license shall be approved for a period of
one year after the applicant's license has been revoked.
Section VII—Enforcement; Notices; Hearings; Orders
7.1 Whenever the (health officer) determines that there are reasona-
ble grounds to believe that there has been a violation of any provision
of this act or of any rule, or regulation adopted pursuant thereto, he
shall give written notice of such alleged violation to the person or
persons responsible therefor as hereinafter provided. Such notice
shall:
7.1.1 Include a statement of the reasons why it is being issued,
citing the provisions of the ordinances or regulations
involved.
7.1.2 Allow a reasonable time for the performance of any act
it requires; be served upon the owner or his agent, or the
occupant, as the case may require: Provided, that such
notice shall be deemed to be properly served upon such
owner or agent, or upon such occupant, if a copy thereof
is served upon him personally; or if a'copy thereof is sent
by registered mail to his last known address; or if he is
served with such notice by any other method authorized
or required under the laws of this State.
7.1.3 State that unless a condition described is corrected within
the specified period of time, any permit issued under this
ordinance may be suspended or revoked, or court action
initiated.
7.2 Any person, affected by any such notice may request and shall
be granted a hearing on the matter before the (health officer): Pro-
vided, that such person shall file, in the office of the (health officer).
a written petition requesting such hearing and setting forth a brier
statement of the grounds therefore within 10 days after the notice
was served. Upon receipt of such petition, the (health officer) shall
set a time and place for such a hearing not later than 10 days after
the filing of the petition and shall give the petitioner written notice
thereof. Provided, that upon application of the petitioner, the
(health officer) shall postpone the date of the hearing for a reasonable
time beyond such 10-day period, if, in his judgment, the petitioner
has submitted a good and sufficient reason for such postponement.
7.3 Based upon the findings of such hearing, the (health officer) shall
sustain, modify, or withdraw the notice, or initiate such enforcement
action as he may deem necessary. If the (health officer) sustains or
modifies such notice, it shall be deemed to be an order. Any notice
served pursuant to subsection 7.1 of this section shall automatically
become an order if a written petition for a hearing is not filed in the
office of the (health officer) within 10 days after such notice is served,
and the health authority may issue an order suspending or revoking
the permit, or court action may be initiated if a reinspection indicates
117
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appropriate corrective action has not been taken within the time
specified in the notice.
7.4 The proceedings at such hearing, including the findings and
decision of the (health officer), shall be summarized, reduced to writ-
ing, and entered as a matter of public record in the office of the (health
officer). Such record shall also include a copy of every notice or
order issued in connection with the matter. Any person aggrieved
by the decision of the (health officer) may seek relief therefrom in
any court of competent jurisdiction, as provided by the laws of this
State.
Sec/ion VIII—Penalties
8.1 Any person who violates any provision of this ordinance, or any
provision of any regulation adopted by the health officer pursuant
to authority granted by this ordinance, shall upon conviction, be pun-
ished by a fine of not less than dollars or more than days and
each day's failure to comply shall constitute a separate violation;
Section IX—Conflict of Ordinances, Effect of Partial Invalidity
9.1 In any case where a provision of this ordinance is found to be
in conflict with a provision of any zoning, building, fire, safety, or
health ordinance or code of this (name of political subdivision) exist-
ing on the effective date of this ordinance, the provision which, in the
judgment of the health officer, establishes the higher standard for the
promotion and protection of the health and safety of the people shall
prevail. In any case where a provision of this ordinance is found to
be in conflict with a provision of any other ordinance or code of the
(name of the political subdivision) existing on the effective date of
this ordinance, which establishes a lower standard for the promotion
and protection of the health and safety of the people, the provisions
of this ordinance shall be deemed to prevail, and such other ordinance
or codes are hereby declared to be repealed to the extent that they
may be found in conflict with this ordinance.
9.2 If any section, subsection, paragraphs, sentence, clause, or phrase
of this ordinance should be declared invalid for any reason whatso-
ever, such decision shall not affect the remaining portions of this
ordinance, which shall remain in full force and effect; and, to this
end, the provisions of this ordinance are hereby declared to be
severable.
Section X—Effective Date
10.1 This ordinance shall be effective on and after the day of
, 19__, provided that section VI shall become
effective on day of 19 .
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INDEX
Abandoned wells, 47, protection of, 47
Acidity, 11
Activated carbon, in taste and odor
control, 78
Aeration, in taste and odor control, 82
Algae, control of, 81
Alkalinity, 10
Alkyl benzene sulfonate (ABS), 6
Aquifer, 2
Arsenic, 8
Artesian springs, 24
Artesian water, definition, 2
Artesian wells, 24
definition, 24
special considerations'in
constructing, 48
Bacteria, Coliform, reduction, 11
Bacteriological quality of water,
determination, 110
Bacteriological tests of water samples,
12
Barium, 8
Basin yield, 22
Boiling, use in small-scale disinfec-
tion, 111
Bored wells, 31
construction, 33
disinfection, 45
yield, 29
Cadmium, 8
Calicuin hypochlorite, use In disinfec-
tion of wells, 43
Capillary fringe, 2
Carbon dioxide, 80
Catchments, controlled, 54
construction, 56
definition, 54
size, 55
suitable location for, 55
Centrifugal pumps, 85
Chemical disinfection, 67
Chlorides, 8
Chlorination, control of, 73
Chlorine, 67, 68, 70, 111
as a water disinfectant, 67
in reducing taste and odor in
water, 79
Chlorine compounds and solutions, 68
Chlorine demand, 69
Chlorine feed or dosage, 69
Chlorine residual, 69, 70
combined available, 69
free available, 69
total available, 69
determination of, 70
test kits, 70
Chromium, 8
Cisterns, 4, 56
Coagulation, as water treatment
process, 65
Color, as physical characteristic of
water, 6
Conditioning, water, 75
Copper, 8
Copper sulfate, In algae control, 79
Corrosion, 79
association with scale, 80
control of, 79
definition, 79
prevention of, 80
Cyanide, 8
Dechlorination, 72
Development of wells, methods, 40
Disinfection, emergency, methods, 111
Disinfection of springs, 51
Disinfection of wells, bacteriological
tests following, 47
Distribution systems, 95
disinfection of, 100
sanitary protection of, 100
Drainage ditches, 23, 24, 51, 54
Drawdown, 26
Drilled wells, 29, 31, 36
construction, 36
percussion (cable tool) meth-
od, 36
rotary hydraulic drilling
method, 36
disinfection, 45
methods of screen installation, 39
pull-back, 39
open-hole, 39
bail-down, 39
wash-down, 39
Driven wells, 35
construction, 35
disinfection, 45
Dug wells, 28, 31, 33
construction, 31
disinfection, 44
reconstruction of existing, 48
Equipment, 71, 86
chlorination, 71
pumping, 86
housing of, 93
sanitary protection of, 90
selection of, 86
Evaporation, as part of hydrologic
cycle, 1
Federal Radiation Council, 13
Filters, 65
types used in treating water, 65
activated carbon, 62
dlatomaceous earth, 66, 67
Pasteur, 66
pressure sand, 66
slow sand, 65
Filtration, as water treatment proc-
ess, 6fi
Fissure springs, 26
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Flowing artesian welts, 46
Fluoridation, 78
Fluorides, 8
Gravity springs, 25
Ground water, 2, 5
development of, 24
by springs, 48
by wells, 26
sanitary quality of, 22
as source of a water supply, 2
Ground-water basins, 22
Ground-water supplies, 19
Grouting, cement, recommended pro-
cedure, 108
Hardness, as a characteristic of water,
10
Heat, as method of disinfection, 74
Hydrogen sulfide, 79
Hydrologic cycle, 1
Hypochlorinators, 71
types, 71
aspirator feeders, 71
positive displacement feeders,
71
suction feeders, 71
tablet hypochlorinators, 72
Infiltration galleries, 51
Iodine, use in small-scale disinfection,
112
Iron bacteria, 76
Irrigation canals, 63
Jet pumps, 86
Jetted wells, 35
Lead, 9
Lime-soda ash, 78
Manganese, 9
Milligrams per liter, 8
Most probable number (MPN), 11
National Fire Protection Association,
15
Nitrates, 9
Nonartesian wells, 24
Odor, as physical characteristic of
water, 6
Orthotolidine, 70
Percussion drilling, 36
pH, as measurement of hydrogen ion
concentration in water, 11
PHS Drinking Water Standards, 11
Pipes and fittings, distribution, 95
materials, 95
sizes, 95
types, 95
protection of, 100
Planning guide for water use, 16
Planning of water systems, 1
Ponds or lakes, 58
source, 58
intakes, 60
treatment, 60
special considerations, 61
Positive displacement pumps, 84
Precipitation, 2, 5
Pumps, 84
installation of, 91
over-the-well, 91
types, 84
Purification, water, 64
Radiation Protection Guides, 13
Radioactivity, 13
Radius of influence, 26
Rates of water flow for certain plumb-
ing, household and farm fixtures, 18
Reciprocating plunger pumps, 84
Reducing agents, 73
Reservoirs, ground-water, 5
Rock formations, in relation to water
bearing properties, 21
classification, 21
igneous, 21
metamorphic, 21
sedimentary, 21
Rotary hydraulic drilling, 36
Sanitary survey, 18
essential parts of, 18
frequency of, 18
importance of, 18
persons qualified to conduct, 18
Screen and casing installations in
wells, 39
Sedimentation, as water treatment
process, 65
Seepage, springs, 25
Selenium, 8
Silver, 8
Snow, hail & sleet, 5
Sodium, 10
Sodium arenslte, 70
Sodium hypochlorite, 68
Springs, 4, 25, 48
development of, 48
disinfection of, 51
sanitary protection of, 50
types, 25
Streams, as a source of surface water
supply, 03
Sulfates, 10
Sulphur water, 79
Superchlorination, 72
Surface water, 4, 5, 53
definition of, 4
for rural use, 63
sources of, 53
taste and odor in, 62
as source of a water supply, 4
Surface-water supplies, 19
Surging, 40
120
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Storage of water, 101
protection of facilities for, 102
types of facilities for, 101
elevated storage tanks, 102
ground-level reservoirs and
cisterns, 102
pressure tanks, 101
Taste, as physical characteristic of
water, 6
Temperature, as physical character-
istic of water, 6
Tincture of iodine, 112
Toxic substances, 8
Transpiration, as part of hydrologic
cycle, 2, 4
Tubular springs, 25
Turbidity, as physical characteristic
of water, 6
Water disinfection, 67
chemical disinfection, 67
heat treatment, 74
other methods and materials, 7
Water quality, 5
biological, chemical, physical and
radiological factors altering
toxicity, 6, 7
Water quantity, 13
average daily consumption, 14
peak demands, 14
Water rights, 1
appropriative, 1
prescriptive, 1
riparian, 1
Water samples, 12
collection, 11
bacteriological examination, 11
chemical analysis, 12
Water softening, 76
ion exchange progress, 77
lime-soda ash process, 78
Water source, selection, 1
Water supplies, 19
Water table, 2
Water treatment, 64
Well construction, 31
Wells, 4, 24, 26, 31
abandonment, 47
construction, 31
development, 40
disinfection, 43
sanitary protection, 41, 42, 43
testing for yield and drawdown,
40
types, 31
as source of a water supply, 4
Yield of wells, 4, 15, 28
safe, 4
sustained, 4
Zinc, 10
Zone of saturation, 2
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